Visalia City Council
August 17, 2026

CITY OF VISALIA
Master Plans and Financial Nexus Study
Stormwater Master Plan
August 2026 / FINAL DRAFT

1401 FULTON STREET, SUITE 802 ▪ FRESNO, CALIFORNIA 93721 ▪ P 559-436-6616

CITY OF VISALIA
Master Plans and Financial Nexus Study
Stormwater Master Plan
August 2026 / FINAL DRAFT

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY i
pw://Carollo/Client/CA/Visalia/11246A00/Deliverables/Stormwater Master Plan/N_SWMP.docx

Contents
EXECUTIVE SUMMARY ES-1
ES.1 Existing Conditions and Future Conditions Modeling ES-1 ES.1.1 USEPA-SWMM Modeling – Storm Drains, Basins, and Pumps ES-1 ES.1.2 Major Drains and Waterways Modeling ES-2
ES.2 Existing Conditions vs. Future Conditions Storm Events ES-2 ES.2.1 Existing Conditions Storm Event ES-2
ES.2.2 Future Conditions Storm Event ES-3
ES.3 Existing Conditions Modeling Results and Recommendations ES-3 ES.3.1 Recommendations ES-3
ES.4 Future Conditions Modeling Results and Recommendations ES-3 ES.4.1 Recommendations ES-4
ES.5 Significant Changes Since the 1994 SWMP ES-4
ES.5.1 Modern Modeling Technology ES-4
ES.5.2 Revised Planning Area ES-4
ES.5.3 Updated Data and Rainfall Information ES-5
ES.5.4 Water Quality and Regulatory Compliance ES-5
ES.5.5 Updated Waterway Capacity Evaluation ES-5
ES.5.6 Change in Focus to Stand-Alone Retention Basins ES-5 ES.5.7 From Planning Study to Implementation Tool ES-6
ES.6 Overall Findings ES-6
CHAPTER 1 INTRODUCTION 1-1

1.1 Background 1-1

1.1.1 2030 General Plan 1-1

1.1.2 Federal Emergency Management Agency Community Rating System 1-3

1.1.3 Shared Use Waterways 1-3

1.2 History 1-3

1.2.1 Historic Flooding 1-3

1.2.2 1994 Stormwater Master Plan 1-4

1.2.3 2005 Stormwater Management Program 1-5

1.2.4 City’s Storm Drainage Design Criteria 1-5

1.3 Purpose 1-5

1.3.1 Objectives 1-6

1.4 Report Organization 1-6
CHAPTER 2 EXISTING CONDITIONS 2-1

2.1 Drainage System Overview 2-1

2.1.1 System Function and Design Characteristics 2-1

2.2 Current Drainage Concerns 2-3

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2.2.1 System Constraints (Capacity and Operational Limitations) 2-3

2.2.2 Localized Deficiencies (Collection and Conveyance) 2-3

2.3 Major Drainage Basins 2-4

2.3.1 St. John’s Drainage Basin 2-5

2.3.2 Modoc Ditch Drainage Basin 2-5

2.3.3 Mill Creek Drainage Basin 2-5

2.3.4 Evans Ditch Drainage Basin 2-6

2.3.5 Packwood Creek Drainage Basin 2-6

2.3.6 Cameron Creek Drainage Basin 2-6

2.3.7 Persian/Watson Drainage Basin 2-6

2.3.8 Goshen Drainage Basin 2-7

2.4 Storage Basins 2-7

2.5 Pump Stations 2-11

2.6 Storm Drainpipe 2-15

2.7 Ditch and Channel Capacities 2-17

2.8 Ditch and Channel Use Agreements 2-17
CHAPTER 3 BASIS OF DESIGN 3-1

3.1 Level of Protection 3-1

3.1.1 Storm Drainage Design Criteria 3-1

3.1.2 Stormwater Master Planning Criteria 3-2

3.2 Low Impact Development 3-4

3.3 Software Programs and Available Data 3-5
CHAPTER 4 HYDROLOGIC ANALYSIS 4-1

4.1 Modeling Approach 4-1

4.1.1 Previous Plan 4-1

4.1.2 Current Plan 4-1

4.2 Scenarios 4-2

4.3 Subcatchment Delineation 4-2

4.4 Rainfall Data 4-5

4.5 Infiltration 4-6

4.5.1 Existing Conditions 4-6

4.5.2 Future Conditions 4-8

4.6 Subcatchment Width 4-8

4.7 Subcatchment Slope 4-12

4.8 Percent Imperviousness 4-12

4.9 Subcatchment Subareas 4-12

4.9.1 Pervious Depression Storage (Initial Abstraction) 4-12

4.9.2 Pervious Surface Roughness (Manning’s n) 4-13

4.9.3 Subarea Routing 4-13

4.10 Assumptions and Limitations 4-13

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CHAPTER 5 HYDRAULIC ANALYSIS OF WATERWAYS 5-1

5.1 Waterway Overview 5-1

5.2 Modeling Approach 5-1

5.3 Major Drainage System Inflows 5-3

5.4 Channel Capacity Analysis 5-8

5.4.1 HEC-RAS 5-9

5.4.2 Federal Highway Administration Hydraulic Toolbox 5-9

5.5 Channel Capacity Results 5-9

5.5.1 Modoc Ditch 5-9

5.5.2 Mill Creek 5-10

5.5.3 Evans Ditch 5-10

5.5.4 Packwood Creek 5-11

5.5.5 North Mill Creek 5-11

5.5.6 Persian/Watson Ditches 5-11

5.6 Assumptions and Limitations 5-12
CHAPTER 6 HYDRAULIC ANALYSIS OF INTERIOR DRAINAGE SYSTEM 6-1

6.1 Modeling Objectives 6-1

6.2 Current and Previous SWMP Modeling Approach 6-1

6.2.1 1994 SWMP 6-1

6.2.2 Current SWMP 6-1

6.3 Existing Conditions Model Components 6-2

6.4 Existing Conditions Model Results 6-6

6.5 Future Conditions Model Components 6-9

6.6 Future Conditions Model Results 6-11

6.7 Assumptions and Limitations 6-15
CHAPTER 7 STORMWATER MANAGEMENT ALTERNATIVES 7-1

7.1 Level of Protection 7-1

7.2 Stormwater Storage 7-2

7.3 Temporary Storage Basins 7-3

7.4 Stormwater Conveyance 7-3

7.5 Entitlement Flow Management Alternatives 7-4

7.6 Assumptions and Limitations 7-5
CHAPTER 8 PROPOSED IMPROVEMENTS 8-1

8.1 Capital Improvement Project Cost Estimates 8-1

8.2 Existing Conditions - Capital Improvement Projects 8-3

8.3 Future Conditions - Capital Improvement Projects 8-5

8.4 Assumptions and Limitations 8-8

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CHAPTER 9 WATER QUALITY MEASURES 9-1

9.1 Background 9-1

9.2 Stormwater Management Program 9-2

9.3 Water Quality Considerations 9-3

9.4 Assumptions and Limitations 9-4
CHAPTER 10 DESIGN CRITERIA FOR MASTER PLAN IMPLEMENTATION 10-1

10.1 Use of Stormwater Master Plan 10-1

10.2 Design Storm and Level of Protection 10-1

10.3 Accepted Calculation Methods 10-2

10.4 Tributary Area and Drainage Boundary Confirmation 10-2

10.5 Future Storm Drain Design 10-2

10.6 Future Storage Basin Design 10-3

10.7 Pump Stations, Wet Wells, and Controlled Discharge 10-3

10.8 Pipe Oversizing and Reimbursement Considerations 10-3

10.9 Cost Estimating and Funding Implementation 10-4

10.10 Deviations from the Master Plan 10-4

10.11 Model Updates and Documentation 10-5
CHAPTER 11 RECOMMENDATIONS FOR FUTURE STUDIES 11-1

11.1 Development Review Integration 11-1

11.2 Project Dependency and Phasing Review 11-1

11.3 As-Built and GIS Data Management 11-1

11.4 Periodic SWMP Implementation Review 11-2

11.5 Future SWMP Updates 11-2

11.6 Model Update Tracking 11-2

11.7 Cost Update and Funding Support 11-3

11.8 Aging Infrastructure and Culvert Replacement Planning 11-3

11.9 Operations and Maintenance Cost Evaluation 11-3

11.10 CIP Tracking and Implementation Dashboard 11-4

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Appendices

APPENDIX A AGREEMENT PROVISIONS BY FACILITY

APPENDIX B STORM DRAINAGE DESIGN CRITERIA

APPENDIX C EXISTING CONDITIONS HYDROLOGIC PARAMETERS

APPENDIX D FUTURE CONDITIONS HYDROLOGIC PARAMETERS
APPENDIX E EXISTING CONDITIONS – MODEL JUNCTIONS AND DIVIDERS, CONDUITS, STORAGE

AREAS, PUMPS, AND OUTFALLS
APPENDIX F EXISTING CONDITIONS MODEL RESULTS – FLAGGED JUNCTIONS AND STORAGE AREAS APPENDIX G FUTURE CONDITIONS – MODEL JUNCTIONS AND DIVIDERS, CONDUITS, STORAGE

AREAS, PUMPS, AND OUTFALLS

APPENDIX H FUTURE CONDITIONS MODEL RESULTS - JUNCTIONS AND STORAGE AREAS

APPENDIX I EXISTING CAPITAL IMPROVEMENT PROJECTS - CUT SHEETS

APPENDIX J FUTURE CAPITAL IMPROVEMENT PROJECTS - CUT SHEETS Tables
Table 1.1 Report Organization with Descriptions 1-6
Table 2.1 Maximum Winter Entitlement 2-2
Table 2.2 Existing Storage Facilities 2-7
Table 2.3 Existing Stormwater Pumps 2-11
Table 2.4 Storm Drain Pipe Length and Diameter 2-15
Table 2.5 Channel Capacities 2-17
Table 3.1 Storm Drainage Design Criteria Level of Protection 3-2 Table 3.2 Software Programs 3-5
Table 3.3 Available Data 3-5
Table 4.1 Precipitation Depth-Duration-Frequency from 1994 SWMP 4-5 Table 4.2 Current Precipitation Depth-Duration-Frequency 4-5 Table 4.3 Composite Curve Numbers for specific HSG and NLCD Landcover 4-7 Table 5.1 Outfalls and Storage Basins along Waterways 5-3 Table 5.2 Existing Conditions Stormwater Outfall Peak Flows 5-3 Table 5.3 Future Conditions Stormwater Outfall Peak Flows 5-8 Table 5.4 Steady-Flow Profile Values 5-9
Table 5.5 Persian/Watson Ditches 5-12
Table 5.6 Estimated Flow Capacity for the Waterways and the Historic Maximum Flow 5-12 Table 6.1 Summary of Existing Conditions Model Update 6-3 Table 6.2 Summary of Future Conditions Model Update 6-10 Table 7.1 Entitlement Flows and Volumes 7-4
Table 8.1 Associated Project Cost Assumptions 8-1
Table 8.2 Cost Values for Project Components 8-2
Table 8.3 Existing Conditions CIPs Brief Descriptions and Costs 8-3 Table 8.4 Future Conditions CIPs Brief Descriptions and Costs 8-5

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Figures
Figure 1.1 Study Area and Urban Boundary Development Tiers 1-2 Figure 2.1 Exhibit 1 from the 1994 SWMP - Major Drainage Basins 2-4 Figure 2.2 Existing Storage Basins 2-10
Figure 2.3 Existing Pump Stations 2-14
Figure 2.4 Existing Storm Drain System 2-16
Figure 4.1 Existing Conditions Model Subcatchments 4-3
Figure 4.2 Future Conditions Model Subcatchments 4-4
Figure 4.3 Hydrologic Soil Groups 4-9
Figure 4.4 Existing Conditions Land Cover 4-10
Figure 4.5 2030 General Plan Land Use 4-11
Figure 5.1 HEC-RAS Modeled Reaches 5-2
Figure 5.2 Modoc Ditch Outfalls and Nearby Storage Basins 5-4 Figure 5.3 Mill Creek Outfalls and Nearby Storage Basins 5-5 Figure 5.4 Evans Ditch Outfalls and Nearby Storage Basins 5-6 Figure 5.5 Packwood Creek Outfalls and Nearby Storage Basins 5-7 Figure 6.1 Existing Conditions Model Components 6-4
Figure 6.2 Existing Conditions Maximum Junction HGL Results 6-7 Figure 6.3 Existing Conditions Maximum Storage HGL Results 6-8 Figure 6.4 Future Conditions Model Components 6-12
Figure 6.5 Future Conditions Maximum Junction HGL Results 6-13 Figure 6.6 Future Conditions Maximum Storage HGL Results 6-14 Figure 8.1 Existing Conditions Capital Improvements Projects Locations 8-4 Figure 8.2 Future Conditions Capital Improvements Projects Locations 8-7

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Abbreviations
ac-ft acre-feet
BMP Best Management Practices
cfs cubic feet per second
CIP Capital Improvement Projects
City City of Visalia
CN Curve Number
CRS Community Rating System
CWA Clean Water Act
DDF depth-duration-frequency
e/o east of
ESRI Environmental Systems Research Institute
FCIP Future Conditions CIP
FHWA Federal Highway Administration
GIS geographic information system
gpm gallons per minute
HEC-RAS Hydrologic Engineering Center River Analysis System HGL hydraulic grade line
HSG hydrologic soil group
KDWCD Kaweah Delta Water Conservation District
lf linear foot
LID low impact development
LiDAR light detection and ranging
LS lump sum
MCM minimum control measures
MS4 Municipal Separate Storm Sewer System
N/A not applicable
n/o north of
NE northeast
NLCD National Land Cover Database
No. number
NOAA National Oceanic and Atmospheric Administration
NPDES National Pollutant Discharge Elimination System
NRCS Natural Resources Conservation Service
NW northwest
RCP reinforced concrete pipe
ROW right-of-way
s/o south of

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MASTER PLANS AND FINANCIAL NEXUS STUDY viii
SE southeast
sf square foot (feet)
SW southwest
SWMP Stormwater Master Plan
SWMM Storm Water Management Model
TID Tulare Irrigation District
UGB Urban Growth Boundary
USACE United States Army Corps of Engineers
USDA United States Department of Agriculture
USEPA United States Environmental Protection Agency
USGS United States Geological Survey
w/o west of
WSS Web Soil Survey
y3 cubic yard(s)

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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY ES-1

EXECUTIVE SUMMARY
The 2026 Stormwater Master Plan (SWMP) represents an update to the hydrologic and hydraulic evaluation of Visalia's stormwater system. This SWMP updates the 1994 SWMP and references applicable sections of the City of Visalia’s (City’s) 2005 Stormwater Management Program. The primary objective of this update was to determine how the existing stormwater system performs today, identify current deficiencies, evaluate the impacts of future growth, and develop a long-term infrastructure strategy that supports continued development while reducing flooding risks and maintaining regulatory compliance.

The study area has been updated to include the revised growth assumptions from the Visalia 2030 General Plan dated October 2014 and the waterways and basins located outside the current City boundary to the east and west. Additionally, data categorizing the City’s stormwater management system has been incorporated into the models to determine existing deficiencies of waterways, basins, and pipes, and to plan for future growth and development.

The City operates and maintains an extensive municipal storm drainage system that includes drainage channels (referred to in this document as major drains), 71 stormwater basins, 51 stormwater pumps at 40 locations, and more than 290 miles of storm drain pipe. The City is defined by eight major drainage basins, including St. John’s Basin, Modoc Ditch Basin, Mill Creek Basin, Evans Ditch Basin, Packwood Creek Basin, Cameron Creek Basin, Persian/Watson Basin, and Goshen Drain Basin.

Runoff is either discharged directly to the major drains, discharged from collector pipes, routed to storage basins, or pumped from storage basins or low-lying drainage areas to downstream receiving facilities.

Some storage basins are terminal facilities that drain only through percolation, evaporation, or evapotranspiration rather than pumped discharge to a major drain.

ES.1 Existing Conditions and Future Conditions Modeling The SWMP used two industry-standard computer modeling programs that work together to evaluate the City's drainage system.

ES.1.1 USEPA-SWMM Modeling – Storm Drains, Basins, and Pumps The United States Environmental Protection Agency (USEPA) Storm Water Management Model (SWMM) was used to evaluate Visalia's internal stormwater infrastructure, including:
 Existing and future runoff.
 Storm drain pipes.
 Pump stations.
 Wet wells.
 Detention and retention basins.

The SWMM model estimates how rainfall becomes runoff and then tracks how water moves through the City's underground infrastructure. It can represent pressurized pipelines, pump operations, flow reversals, and system interactions that commonly occur in flat areas such as Visalia.

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ES.1.2 Major Drains and Waterways Modeling
The Hydrologic Engineering Center River Analysis System (HEC-RAS) was used to perform planning-level hydraulic capacity screening for Modoc Ditch, Mill Creek, Evans Ditch, and Packwood Creek. The Federal Highway Administration (FHWA) Hydraulic Toolbox was used for North Mill Creek and the Persian/Watson Ditches. These evaluations considered channel geometry, roadway crossings, inline structures, backwater, and the onset and extent of channel-bank overtopping.

This waterway modeling was used to determine:
 Planning-level waterway capacity ranges.
 Locations and flow ranges associated with channel-bank overtopping.  Downstream hydraulic constraints.
 Roadway crossings, inline structures, and other localized hydraulic controls.  Potential bottlenecks within the receiving channels.

The HEC-RAS analysis is particularly important because many of Visalia's drainage facilities discharge into waterways that also carry irrigation water and regional flood-control flows. During periods when those waterways are already carrying irrigation or flood releases, available capacity for local stormwater runoff is reduced.

Together, these evaluations provide a planning-level understanding of how runoff moves through the City’s interior drainage system and how receiving-water constraints affect feasible stormwater-management strategies.

ES.2 Existing Conditions vs. Future Conditions Storm Events One of the most important distinctions in the SWMP is that Existing Conditions and Future Conditions were analyzed using different storm event assumptions.

This distinction is important because Visalia relies heavily on storage basins and controlled pumping rather than simply conveying water away quickly. Future infrastructure therefore must be designed not only for individual storms but also for repeated storms that occur before facilities have fully drained. This results in a more conservative and realistic planning framework for future growth.

ES.2.1 Existing Conditions Storm Event
The Existing Conditions analysis was performed to determine whether today's infrastructure adequately serves today's community and to identify current deficiencies. The Existing Conditions analysis evaluates whether infrastructure serving the developed City performs generally consistent with the historical design basis under which much of the system was constructed.

The modeling utilizes a storm depth and duration developed by the City that emulates the City’s Storm Drainage Design Criteria for Minor Drains. Modeling results were verified with City staff that operate the system.

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MASTER PLANS AND FINANCIAL NEXUS STUDY ES-3
ES.2.2 Future Conditions Storm Event
The Future Conditions analysis was performed to determine the stormwater infrastructure needed to serve tomorrow’s community, specifically for the backbone portions of the future system. The backbone of the City’s system includes regional storm trunklines, regional storage basins, and regional storm pump stations. The backbone is generally sized to capture more water to prevent adverse impacts downstream.

The storm depth and duration for the Future Conditions evaluation was developed by the City to follow the City’s design standards for the backbone of the system, referred to as “Major Drains” in the City’s Drainage Design Criteria. Modeling results were verified using observations from stormwater infrastructure constructed for more recent areas of the City.

ES.3 Existing Conditions Modeling Results and Recommendations The Existing Conditions analysis concluded that the City's overall drainage system is performing largely as intended. Most major storm drains, basins, and pump facilities provide acceptable drainage service under current development conditions.

However, several localized issues were identified.

Area 1 – South County Center Drive and Walnut Avenue. Flooding occurs due to insufficient wet well capacity and the absence of an overflow route to Evans Ditch. This issue is primarily related to localized storage limitations rather than a major network deficiency.

Area 2 – Houston Avenue and McAuliff Street. Recurring flooding and debris accumulation occur because of a pipe size reduction that promotes clogging and restricts flow.

Area 3 – Kiwanis Park Basin. The basin and wet well system do not fully utilize available storage because of limitations in the hydraulic connection between facilities.

Three Existing Conditions Capital Improvement Projects (CIPs) were developed to address the identified priority areas.

ES.3.1 Recommendations
The SWMP recommends targeted infrastructure improvements to address these identified problem areas, including:
 Wet well modifications.
 Improved overflow connections.
 Localized pipe upgrades.
 Improved basin drainage connections.
 Continued system maintenance and monitoring.

ES.4 Future Conditions Modeling Results and Recommendations The Future Conditions analysis demonstrates that existing infrastructure alone cannot fully support projected future growth.

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The model results identified the need for the following in the areas of projected development:
 Additional regional retention basins.
 New trunk storm drain systems.
 Selected pump and wet-well improvements.
 Controlled outlet connections consistent with receiving-water constraints and applicable agreements.  Strategic regional drainage improvements.

Thirty-five Future Conditions CIPs (FCIPs) were developed to provide the regional storage, trunk conveyance, controlled outlet, and related infrastructure needed to serve General Plan buildout and known future development areas.

ES.4.1 Recommendations
The SWMP recommends continuation of the City's long-standing "storage-first" drainage philosophy by emphasizing:
 Regional stormwater storage.
 Controlled discharges.
 Retention basins.
 Strategic pump station operations.
 Coordinated implementation with future development.

The study also recommends periodic model updates, development review integration, geographic information system (GIS) tracking, infrastructure condition assessments, and long-term capital improvement programming.

ES.5 Significant Changes Since the 1994 SWMP
Several major changes distinguish the 2026 SWMP from the 1994 master plan.

ES.5.1 Modern Modeling Technology
The 1994 SWMP relied primarily on HEC-1 hydrology and simplified hydraulic methods. The new SWMP uses USEPA-SWMM dynamic wave analysis and HEC-RAS hydraulic modeling, allowing much more realistic representation of storage basins, pumps, backwater effects, and interconnected drainage systems.

ES.5.2 Revised Planning Area
The 1994 Plan evaluated the planning area that was in effect at the time of that plan’s development. This plan is updated to evaluate the planning area included in the 2030 General Plan.

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ES.5.3 Updated Data and Rainfall Information
The current models incorporate National Oceanic and Atmospheric Administration (NOAA) Atlas 14 rainfall data, updated GIS and as-built information, City-provided 2006 light detection and ranging (LiDAR), updated pump information, revised basin storage relationships, current General Plan land uses, and updated United States Department of Agriculture (USDA) soil mapping.

ES.5.4 Water Quality and Regulatory Compliance
Since 1994, new regulatory requirements have emerged, including Municipal Separate Storm Sewer System (MS4) permits, National Pollutant Discharge Elimination System (NPDES) requirements, Low Impact Development (LID) requirements, and hydromodification controls. The updated SWMP incorporates these requirements into future planning using the 2005 Stormwater Management Program (an MS4 permit compliance document) as a complement. LID and hydromodification requirements remain applicable to qualifying development and redevelopment projects. However, runoff-reduction, flow- control, and storage benefits attributable to project-specific LID measures were not credited in hydrologic modeling or in sizing the master-planned storm drainpipes and storage basins. This conservative approach avoids relying on measures that may vary by project, timing, implementation, and long-term maintenance.

ES.5.5 Updated Waterway Capacity Evaluation
The updated planning-level waterway capacity ranges are generally lower than the broad ranges reported in the 1994 SWMP for several major drains. The difference primarily reflects the use of detailed cross sections, roadway crossings, inline structures, backwater, and localized hydraulic controls that were not represented in the simplified 1994 Manning’s-equation analysis. The updated ranges do not, by themselves, demonstrate that the physical waterways have lost capacity since 1994. Because survey information was unavailable for some crossings, the results remain appropriate for planning-level screening and should be confirmed before designing specific channel or culvert improvements.

ES.5.6 Change in Focus to Stand-Alone Retention Basins
The 1994 SWMP emphasized temporary storage through detention facilities, whereas this plan utilizes retention basins for future development. This approach reduces the City’s reliance on downstream conveyance facilities.

Additionally, the 1994 plan recommended multipurpose detention park basins, while this plan provides for standalone retention basins.

In 2025, Parks, Public Works, the City Manager, the Director of Finance, and Engineering agreed to abandon the combination park-basin approach. While basins will still be located adjacent to parks where feasible, consensus was reached that given the City’s shift from detention to retention, combination park- basins will not be practical moving forward. All regional basins moving forward will be designed as standalone retention basins.

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ES.5.7 From Planning Study to Implementation Tool
The 2026 SWMP provides a detailed roadmap for implementation, including CIPs, planning-level cost estimates, development review guidance, funding support tools, and recommendations for maintaining and updating the City's drainage models.

ES.6 Overall Findings
Visalia's stormwater system is generally serving the community well today, but future growth will require significant investment in regional storage, conveyance, pumping, and drainage infrastructure. The City's greatest challenge is not widespread current flooding, but proactively preparing for future development while managing downstream capacity limitations, aging infrastructure, and evolving regulatory requirements. The 2026 SWMP provides an updated technical and implementation framework for prioritizing capital improvements, coordinating infrastructure with future development, managing downstream discharge constraints, and maintaining the City’s stormwater models and planning tools over time.

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CHAPTER 1 INTRODUCTION

1.1 Background
The City is located east of State Highway 99 and along State Highway 198. The City’s population is approximately 146,000. The incorporated area covers approximately 41 square miles. Figure 1.1 shows the study area, current municipal boundary, and the Urban Development Boundary Tiers.

1.1.1 2030 General Plan
The City released the Visalia 2030 General Plan in October 2014. The General Plan sets the goals, policies, and implementation tools for the orderly, planned growth of the City. The General Plan also requires public facility master plans to be developed, maintained, and implemented to ensure adequate levels of service for the growth of the City. This document serves as the SWMP for the City.

The General Plan emphasizes increased land use densities and infill development compared with previous growth assumptions, which reduced the planned urban footprint needed to accommodate buildout within the Tier 3 UGB.

The General Plan specifies several policies directly related to stormwater management:

1. Policy P-46 directs the City to continue in an active role in regional and local water management planning. For stormwater, this policy supports the configuration of stormwater facilities that retain and recharge as much stormwater as practical within and near the City, including diversion to off-stream storage basins where feasible. This policy is also important because the City is a member of the Mid-Kaweah Groundwater Sustainability Agency, where stormwater retention and recharge are key components of long-term groundwater sustainability planning.

2. Policy P-57 requires updates to public facility master plans related to infrastructure development to ensure that existing levels of service can be maintained for proposed land uses and development densities.

3. Policy P-61 requires the City to establish a Stormwater Management Program and adopt a Stormwater Management Ordinance to minimize stormwater runoff rates and volumes, control water pollution, meet regulatory requirements, and maximize groundwater recharge. Policy P-61 is implemented through compliance with the City’s MS4 General Permit.

4. Policy P-62 requires updating the SWMP to provide site-appropriate solutions that protect surface water quality and meet regulatory requirements as directed by the Stormwater Management Program.

Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

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Figure 1.1 Study Area and Urban Boundary Development Tiers

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
Saint Johns River
Railroads
City Limits
County Parcels
Public Urban Development
Growth Tiers
Urban Development
Boundary Tier 1
Urban Development
Boundary Tier 2
Urban Growth Boundary
Tier 3
Vicinity Map
City of
Visalia

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1.1.2 Federal Emergency Management Agency Community Rating System The City participates in the Federal Emergency Management Agency Community Rating System (CRS) Program and is committed to improving floodplain management practices to the benefit of the community. The SWMP incorporates CRS Program elements including local drainage protection, stormwater management regulations, and watershed master planning.

1.1.3 Shared Use Waterways
Visalia’s stormwater system is shaped by a unique receiving-water constraint: the primary waterways through and around the City function largely as irrigation ditches and managed channels that are often elevated relative to surrounding land and do not provide a natural “downstream outlet” for unlimited storm discharges. Stormwater releases to these waterways are therefore governed by shared-use agreements that limit when and how much the City can discharge, particularly when irrigation deliveries or Lake Kaweah flood control releases occur. As a result, Visalia’s stormwater strategy must balance conveyance, storage, controlled pumping/release, and localized surface ponding in a way that is fundamentally different than communities with large natural receiving waters.

1.2 History
The City developed from agricultural land on the lower portion of an alluvial fan formed by the Kaweah River and its distributary channels at the foot of the Sierra Nevada Range along the eastern edge of the valley. Rainfall for the area averages approximately 10 inches per year. The wet season generally includes the months of November through April, though rainfall can occur year-round. January has the highest average monthly rainfall with nearly two inches. Visalia and the surrounding region frequently experience extended periods of drought, especially during the months of June through October.

Historically, stormwater runoff was directed to natural creeks, rivers, and irrigation ditches that flow through the City. The City had to reevaluate their stormwater policies when irrigation companies responsible for the operation and maintenance of the channels refused to accept additional storm runoff from the City, citing their inability to handle the flows downstream as the channels narrow and lose capacity. The City entered into agreements with the private companies that own and operate the ditches that run through the City and the Districts that operate Packwood and Mill Creeks. The agreements establish conditions under which the City can discharge stormwater into the channels and define the City’s maintenance responsibilities.

1.2.1 Historic Flooding
Historically, flooding within the City has occurred from two primary sources:

1. Overflow or failure associated with larger waterways and regional flood mechanisms.

2. Localized rainfall events producing nuisance flooding within developed areas.

Localized flooding can occur when rainfall intensity exceeds local collection/conveyance capacity or when downstream receiving systems have reduced capacity due to concurrent irrigation or flood flows. Because the City’s topography generally slopes from east to west, overland flow routes also influence where floodwaters collect and how quickly ponded areas can drain.

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Floods within and around the City have historically occurred during December, January, and February as a result of heavy rains combined with snow melt from the foothills and the Sierra Nevada Mountains. Major floods occurred in November 1950, December 1955, December 1966, and January 1969. Prior to the construction of the Terminus Dam, the major sources of flooding were the St. John’s River and the Kaweah River and its distributaries. Now the major sources of flood waters are the upstream overflows of the St.

John’s River and the Lower Kaweah, which move toward Visalia as overland sheet flow.

Before the construction of the Terminus Dam, major floods occurred almost every decade and resulted in shallow flooding across thousands of acres of the alluvial fan surface. The December 1955 flood resulted in the largest peak runoff from the Kaweah River watershed with an estimated recurrence interval of approximately 150 years. Both the 1950 and 1955 floods caused shallow flooding of less than three feet in Visalia, but contributed to extensive damage to streets, bridges, structures, and agricultural property. The largest flood since construction of the Terminus Dam occurred in December 1966, when peak flows into Lake Kaweah reached 105,000 cubic feet per second (cfs), the highest ever recorded. All Kaweah River flows were contained by Terminus Dam, and no releases were made from the reservoir during the flood peak. Significant flooding occurred on the alluvial fan primarily from Yokohl Creek. Shallow flooding from local creek systems such as the Yokohl affected about 25 square miles of mainly agricultural land.

Terminus Dam has a capacity of approximately 150,000 acre-feet (ac-ft) and has been operated for flood control by the United States Army Corps of Engineers (USACE) since 1962. The dam has significantly reduced potential flood hazards of Kaweah River and its distributaries. It is estimated that the dam provides protection against floods with a 50-year recurrence interval. Additional flood control measures were proposed by the USACE and Tulare County Flood Control District.

Agricultural land uses and flow regulation at Terminus Dam have resulted in several significant hydrologic and geomorphic changes in the area. First, following dam completion in 1962, the Kaweah River experienced a drastic reduction in high flows. In response, channel capacity downstream of the dam is reported to have declined from about 20,000 cfs in the 1960s to about 10,000 cfs in the late 1990s.

Second, unregulated distributary channels and local creek systems downstream of the dam are now important sources of flooding in the greater Visalia area, including Dry Creek and Yokohl Creek. Finally, manmade changes in land use such as land leveling, levees, road berms, and drainage ditches now play a significant role in determining the location and distribution of shallow flooding on the alluvial fan surface.

1.2.2 1994 Stormwater Master Plan
The 1994 SWMP divided the study area into eight drainage basins encompassing 35,000 acres, which corresponded with the 2020 Urban Development Boundary defined in the City’s 1991 Land Use Element update to the General Plan. The 1994 SWMP determined the peak discharges to the receiving channels for a design rainfall event and compared those discharges to existing channel capacities. Historic channel flows and water right entitlements were reviewed, and alternatives were developed for managing coincident flows.

This SWMP addresses alternatives to mitigate flooding from local rainfall and builds on the prior SWMP developed in 1994.

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1.2.3 2005 Stormwater Management Program
The 2005 Stormwater Management Program outlined the City’s stormwater related priorities as part of the City’s compliance with the MS4 permit. Six minimum control measures (MCMs) were addressed, including public education and outreach, public involvement and participation, illicit discharge detection and elimination, construction site stormwater runoff control, post-construction stormwater management, pollution prevention and good housekeeping.

1.2.4 City’s Storm Drainage Design Criteria
The City uses the Rational Method for day-to-day drainage design and development review, while master planning relies on computer modeling approaches more appropriate for large tributary areas and systems with detention and retention storage. Updates to design criteria over time, including changes to conveyance and basin design standards, inform how the City evaluates both existing deficiencies and future system needs. These standards have been incorporated into this study’s analysis approach.

1.3 Purpose
This update to the City’s SWMP presents data, modeling, and analysis results for the City’s stormwater basins, pumps, pipe network, and waterways for existing and planned future conditions. The study area was updated to the Tier 3 UGB plus the waterways and basins located outside the boundary to the east and west. Existing and new data were incorporated into the models to determine the existing deficiencies of waterways, basins, and pipes. Additionally, the models can be updated in the future to predict changes during the estimated 10- to 20-year planning horizon of this SWMP.

In addition to evaluating existing and future storm system performance, the updated SWMP is intended to:

1. Provide clear direction for development by identifying tributary areas, recommended pipe sizes/depths, potential basin locations, and basin capacities.

2. Define design criteria and accepted calculation methods.

3. Establish a defensible basis for updating storm funding mechanisms by outlining capital improvements with transparent cost estimating methodology and clear definitions of included versus excluded costs.

This updated SWMP will also support updates to storm service charges by identifying improvements needed to address existing deficiencies, and by including generalized program needs related to MS4 compliance where appropriate. The plan further documents considerations for waterway conveyance and regional flood control coordination, recognizing that receiving capacity limitations and shared-use agreements are central to feasible system solutions.

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1.3.1 Objectives
Consistent with prior master planning, the City recognizes that some degree of moderate street ponding may occur as the urban area continues to develop, and that eliminating street flooding solely through conveyance upsizing is often impractical and cost prohibitive. Accordingly, this SWMP emphasizes an integrated strategy that combines:

1. On-site and regional storage.

2. Pump station discharge management consistent with operational agreements and downstream capacity constraints.

3. Targeted conveyance improvements where they provide measurable, systemwide benefit.

Storage facility sizing also requires careful consideration of outlet limitations. Facilities that rely primarily on infiltration and evapotranspiration (i.e., without an engineered outlet) require different sizing and performance assumptions than detention basins with controlled discharge. In addition, prior master planning has applied different design storm criteria for downstream terminal facilities compared with in-town basins. This SWMP update carries forward that framework and documents its application to support storage strategies that align with City standards, outlet constraints, and system performance objectives.

1.4 Report Organization
The SWMP report has been organized to help readers easily find important information. Table 1.1 provides an overview of each chapter in this SWMP.

Table 1.1 Report Organization with Descriptions
Chapter Description

1. Introduction Provides background and history related to the SWMP update, including a summary of previous studies.

2. Existing Conditions Provides an overview of the City’s stormwater system.

3. Basis of Design Describes the general approach, assumptions, and software needed to conduct the SWMP update.

4. Hydrologic Analysis Describes the hydrologic model and analysis, including subcatchment delineation to runoff calculations.

5. Hydraulic Analysis of Waterways Describes the hydraulic models and analysis of the drainage ditches and channels.

6. Hydraulic Analysis of Basins,
Pumps, and Pipe Network
Describes the hydraulic models and analysis related to the basins, pumps, and pipe network for both the existing and future buildout conditions.

7. Stormwater Management
Alternatives
Evaluates the alternatives considered for future conditions, including level of protection and stormwater storage.

8. Proposed Improvements Provides a discussion of the proposed projects to address future buildout, with planning-level cost estimates and implementation considerations.

9. Water Quality Measures Briefly discusses measures to improve the quality of stormwater discharges.

10. Design Criteria for Master Plan
Implementation
Includes design criteria for and methodology for infrastructure upgrades performed by the City and for new development.

11. Recommendations for Future
Studies
Provides recommendations for future studies based on the outcomes from this plan.

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CHAPTER 2 EXISTING CONDITIONS
This chapter summarizes the existing storm drainage system serving the City, including overall system configuration, primary drainage basins, storage basins, pump stations, and the shared-use major drains that receive City stormwater. The existing system reflects a combination of underground conveyance facilities intended to collect and route frequent storm runoff, distributed storage used to manage runoff when downstream receiving capacity is limited, and pumping facilities required where gravity discharge is constrained by flat topography and tailwater conditions.

The City operates and maintains a vast municipal storm drainage system that consists of drainage channels, 71 stormwater basins, 51 pumps at 40 pump stations, and more than 290 miles of pipe.

Historically, runoff was directed to natural creeks, rivers, and irrigation ditches, including St. John’s River, Mill Creek, Packwood Creek, Modoc Ditch, Evans Ditch, and Persian Ditch.

The City has purchased land and constructed permanent retention basins, including park-pond basins, to mitigate the increased runoff due to urbanization. A defining characteristic of Visalia’s drainage system is its reliance on major drains that also convey irrigation flows and, at times, regional flood releases. As a result, available receiving capacity for stormwater varies seasonally and operationally, and stormwater management relies on a coupled network of conveyance, storage, and controlled discharge rather than conveyance expansion alone.

2.1 Drainage System Overview
The City operates and maintains a municipal storm drainage system consisting of open-channel major drains, stormwater storage basins, pump stations, and an underground storm drain pipe network. The system is organized into eight major drainage basins that generally drain from east to west toward downstream receiving facilities and shared-use waterways.

The City’s minor drainage system collects and conveys runoff to the major drains and consists primarily of catch basins and underground concrete pipes.

2.1.1 System Function and Design Characteristics
The existing storm drainage system is intended to reduce the frequency and extent of nuisance flooding from relatively frequent storms by collecting runoff, temporarily storing excess flow where downstream conveyance is constrained, and discharging stormwater to major drains under controlled conditions. Key characteristics of the system include:
 Minor (collector) conveyance: Catch basins and underground pipes collect runoff and route flow toward major drains and storage basins.
 Storage-first behavior during higher intensities: When rainfall intensity exceeds available pipe capacity, water may pond within streets and other low areas until pipe capacity becomes available and/or ponded water migrates along overland flow paths. This behavior effectively moderates peak inflows to storage basins and downstream waterways.

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 Reliance on controlled discharge: Where major drains are capacity-limited or shared with irrigation/flood conveyance, stormwater discharges are managed using pump station operations, outlet controls, and storage drawdown.
 Dual drainage (surface + subsurface): During larger events, portions of the system may surcharge and route flow along streets and within the public right-of-way (ROW) before returning to the storm drain system or reaching downstream collection points.

2.1.1.1 Major Drainage System
The major drainage system consists primarily of open channels and shared-use ditches/canals that receive stormwater discharges. These facilities are integral to routing runoff across the City and ultimately toward downstream outlets. Because major drains may concurrently convey irrigation deliveries and/or flood releases, the available capacity for stormwater can vary over time, and discharges must remain consistent with allowable flow conditions.

Many of the major drains in the City are jointly used to convey flood water, irrigation water, and stormwater. During the winter months, flood control releases from Kaweah Lake make use of the major drains to convey flood water through the City. The channels and ditches are also used to convey entitled irrigation flows as shown in Table 2.1. The maximum historic flow from 2000 to 2019 provided by Kaweah Delta Water Conservation District (KDWCD) is also shown in Table 2.1. When either irrigation or flood flows are conveyed in the major drains, the capacity for stormwater runoff from the City is reduced.

Agreements between the City and irrigation companies allow the City to improve the conveyance capacity of the channels and ditches or provide equivalent storage and make use of the increased capacity for stormwater conveyance. Agreement provisions by facility are summarized in Appendix A.

Table 2.1 Maximum Winter Entitlement
Channel Maximum Winter Entitlement (cfs) Maximum Historic Flow (2000-2019) (cfs) Packwood Creek 265 300
Mill Creek 99 169
Evans Ditch 54 50
Modoc Ditch 99 86

2.1.1.2 Minor Drainage System
The minor drainage system includes storm drain inlets, underground pipes, manholes, and appurtenances that collect runoff from streets and developed areas. The minor system conveys runoff to the major system and to storage basins. Localized surcharging and street ponding may occur when inflows exceed inlet/pipe capacity, when downstream water levels create backwater conditions, or when discharge constraints limit basin drawdown.

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2.2 Current Drainage Concerns
The regional and historic flooding described in Section 1.2.1 relates primarily to runoff from the Kaweah River Basin. Current drainage challenges generally fall into two categories:

1. System constraints.

2. Localized deficiencies.

The concerns are described more fully below.

2.2.1 System Constraints (Capacity and Operational Limitations) Major flooding is rare in Visalia because the City is relatively flat and ponding does not concentrate in significant, damaging depths. There are several minor or nuisance flooding areas caused by local runoff concentrations. The nuisance flooding will become more frequent if development continues without improving the system. Key system planning considerations include:

1. Variable downstream receiving capacity: Major drains that receive City stormwater are often shared with irrigation conveyance and, at times, regional flood routing. When these flows are present, the available capacity for local stormwater discharge is reduced.

2. Need for controlled discharge and staged drawdown: Because allowable stormwater discharge rates can be constrained, storage basins and pump station operations play a central role in preventing excessive downstream loading while managing localized ponding durations.

3. Flat topography and backwater sensitivity: Low relief and tailwater effects can reduce hydraulic gradients, increase sensitivity to downstream water levels, and increase the likelihood of localized ponding during higher intensity events.

2.2.2 Localized Deficiencies (Collection and Conveyance) Localized deficiencies in the collection and conveyance system can drive nuisance flooding even where the major drainage backbone generally performs as intended. These issues are typically concentrated at discrete segments or appurtenances (e.g., inlets, crossings, transitions) and are influenced by a combination of physical capacity, hydraulic control (tailwater and limited grade), and maintenance condition. The most common localized deficiency types observed are:

1. Undersized or shallow collection/conveyance segments relative to contributing imperviousness and local inlet spacing.

2. Localized bottlenecks at inlets, crossings, or transitions between systems.

3. Sediment, vegetation, and debris accumulation in channels and at inlet structures that reduce effective capacity.

Localized flooding is therefore not solely a function of pipe size. It may also reflect inlet interception limits, localized bottlenecks, maintenance-related reductions in capacity, and the operational constraints of a storage-and-controlled-discharge system where drawdown is governed by downstream receiving conditions.

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The objective of this SWMP is to identify and prioritize improvements that reduce recurring, materially disruptive flooding and improve system performance at the neighborhood and basin scale, including deficiencies that propagate from constraints in the major drainage system. Elimination of isolated, short-duration street ponding at individual inlets or low points is not the intent of this SWMP and is more appropriately addressed through targeted maintenance, inlet modifications, or localized spot improvements.

2.3 Major Drainage Basins
The 1994 SWMP defined eight major drainage basins, including St. John’s Basin, Modoc Ditch Basin, Mill Creek Basin, Evans Ditch Basin, Packwood Creek Basin, Cameron Creek Basin, Persian/Watson Basin, and Goshen Drain Basin. The drainage basin figure from the 1994 SWMP is shown in Figure 2.1. Basin delineations reflect existing topography, the configuration of major drains and collector systems, and the locations of storage basins and pump stations. Runoff from each basin is conveyed via a combination of underground storm drain infrastructure and open-channel facilities and is either discharged directly to a major drain, routed into storage for later release, or pumped to a major drain where gravity discharge is not feasible. The historical perspective of the eight major drainage basins is provided in the following subsections.

Figure 2.1 Exhibit 1 from the 1994 SWMP - Major Drainage Basins

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2.3.1 St. John’s Drainage Basin
The St. John’s Drainage Basin is approximately 3,393 acres and is located in the northeast portion of the City. The area is partially developed and planned for increased residential and commercial development.

The 1994 SWMP determined approximately 2.3 square miles of the basin area drain to the St. John’s River.

The elevation of the riverbank is higher than adjacent land elevations and runoff drains to the river via four pump stations (five total pumps) located along the riverbank.

St. John’s River is regulated by the Kaweah and St. John’s Rivers Associations. The river begins at McKays Point about 12 miles east of Visalia and joins Cottonwood Creek about three miles west of Road 80.

Cottonwood Creek continues to Tulare Lake. St John’s River has a capacity ranging from about 8,000 to 11,000 cfs (per Central Valley Flood Protection Board) in the vicinity of Visalia and is currently maintained by the KDWCD.

2.3.2 Modoc Ditch Drainage Basin
The Modoc Drainage Basin is approximately 8,242 acres and is located in the northern portion of the City along both sides of Modoc Ditch. The area is partially developed, and runoff is pumped to the ditch via six pumps. The 1994 SWMP determined approximately one square mile of the developed area drained to Modoc Ditch.

Modoc Ditch is an open channel irrigation canal that provides irrigation service to about 6,500 acres. The channel begins at the St. John’s River about one-quarter mile west of Ben Maddox Way and ends west of the City at Road 68 in a terminal basin. The upstream flow at the headgate is controlled by the Modoc Ditch Company. The channel splits several times and the capacity of the main channel decreases in the downstream direction.

2.3.3 Mill Creek Drainage Basin
The Mill Creek Drainage Basin is approximately 6,149 acres and is nearly fully developed. The drainage area includes the downtown and other commercial, industrial, and residential areas along both sides of Highway 198. Runoff drains to Mill Creek by gravity drains and pump station discharges.

Mill Creek is a combination of lined, unlined, natural, and closed conduit conveyance systems. Mill Creek begins at a split of the Lower Kaweah River near Road 158, flows through the City, and continues to Cross Creek in Kings County. A north branch splits from the main channel near Tommy Road and continues to Cross Creek.

Irrigation and flood flow at the headwaters are regulated by Kaweah and St. John’s Rivers Associations.

There is no direct irrigation service from the channel, however, it delivers water to the Evans Ditch headgate on the east side of the City and the Persian/Watson Ditch system headgate near Linwood.

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2.3.4 Evans Ditch Drainage Basin
The Evans Ditch Drainage Basin is approximately 1,614 acres and consists of several isolated areas surrounded by the Packwood Creek and Mill Creek Drainage Basins. The basin is mostly fully developed and drains to Evans Ditch by pump stations.

Evans Ditch is an open irrigation canal that begins at Mill Creek near McAuliff Road and flows to Nelson Pit, then beyond to Mill Creek near the County line.

Irrigation and flood flow at the headworks are regulated by the Evans Ditch Company. Both the City and the Evans Ditch Company have a 50 percent share of the channel, and the City maintains the channel within the City limits.

2.3.5 Packwood Creek Drainage Basin
The Packwood Creek Drainage Basin is approximately 5,880 acres and drains the southern part of the City.

Most of the drainage area is developed with some areas under development. The 1994 SWMP determined approximately 5.3 square miles of land drain to Packwood Creek. Areas on the eastern side of the City drain to Packwood Creek by gravity, and areas on the western side drain by pump stations.

Packwood Creek is an unlined natural channel that begins at the split of the Lower Kaweah River near Road 158, flows through Tagus Basin, and continues to the southwest.

Developed areas surround the channel as it passes through the City. At the headworks, flows are regulated by the Tulare Irrigation District (TID), while the City maintains the channel within the City limits.

2.3.6 Cameron Creek Drainage Basin
The Cameron Creek Drainage Basin is approximately 4,781 acres and is located in the southern portion of the City. Most of the Cameron Creek watershed is undeveloped, although significant development is planned in the Visalia 2030 General Plan.

Cameron Creek is an open channel natural stream that historically began at Deep Creek north of Farmersville. The current origin, however, is at TID’s main canal east of Road 156. The Creek connects back with TID’s main canal on the east side of Mooney’s Grove.

Irrigation and flood flow are regulated by TID, which also maintains the channel. Occasionally, water is diverted from the main canal to Cameron Creek for groundwater recharge when excess water is available.

2.3.7 Persian/Watson Drainage Basin
The Persian/Watson Drainage Basin is approximately 1,626 acres and located on the western side of the City south of Highway 198. The Persian/Watson Ditch is an open irrigation canal owned by the Persian Ditch Company and the Watson Ditch Company.

Persian/Watson Ditch starts at Mill Creek near Linwood Street. The North Fork of Persian Ditch crosses Highway 99 and terminates. The Middle and South Forks of Persian/Watson Ditch flow by Miller Basin and connect with Mill Creek or terminate.

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2.3.8 Goshen Drainage Basin
The Goshen Drain Drainage Basin is approximately 3,243 acres and follows Goshen Avenue in the northwestern part of the City. Goshen Drain is a 48-inch reinforced concrete pipe (RCP) that starts on Goshen Avenue near Mooney Boulevard and empties into a large basin (“Goshen Ocean”) on the western side of the City.

The Goshen Ocean also has pumped discharge to the North Fork of Mill Creek, also referred to as Mill Creek Ditch, which provides a downstream outlet for stored runoff when pumping is required.

2.4 Storage Basins
Stormwater storage basins are one part of the City’s municipal storm drainage system. Currently, there are 71 stormwater storage basins ranging in size from 0.2 to 394 ac-ft capacity and a total storage volume of 2,898 ac-ft throughout the system. The footprint of the storage basins range in size from 0.1 to 34 acres, with a total coverage area of 353 acres.

Storage basins provide volume to manage excess runoff during periods when minor-system conveyance capacity is exceeded, when downstream receiving capacity is reduced due to irrigation or flood operations, or when discharge must be controlled to remain consistent with allowable conditions in shared-use major drains. They also provide operational flexibility by enabling staged drawdown and timed pumping or discharge as downstream conditions allow.

Basin performance is therefore closely tied to pump station operations, tailwater conditions, and the practical limits on discharge to major drains. Table 2.2 provides a summary of the existing storage basin locations, capacities, and footprints. Figure 2.2 shows the locations of the storage basins.

Table 2.2 Existing Storage Facilities
Name Type of Basin Location Capacity
(ac-ft)
Footprint
(acre)
American Industrial Park East
Basin
Retention e/o American Street s/o Grove Avenue (NW) 7.8 0.87 American Industrial Park West
Basin
Retention 10529 W Legacy Avenue 9.7 1.06
Auto Mall Basin Retention Century Street & Hillsdale Avenue (SW) 16.9 1.65 Avenue 280/Road 48 (NW) Retention Avenue 280 & Road 48 (NW) 277.3 32.66 Blain Park/Pond Detention S Court Street & Parkview Avenue 7.9 1.93 Brelsford Basin Temporary Plaza Drive (800' East) 33.4 2.48 Briarwood Basin Retention Seeger Avenue & Beech Drive 5.4 0.8 Burke Park/Pond Retention S Burke Street & E Monte Vista Avenue (SW) 27 4.2 C.O.S. Basin Detention and
layoff recharge
Mary Avenue & Crenshaw Street (NW) 20.3 2.02
Cherry Meadow Park/Pond Detention S Pinkham Street & Cherry Avenue 14.9 3.52 Combs Park/Pond Detention S Crenshaw Street & La Vida Avenue 36.4 6.27 Constitution Park/Pond Detention W Tulare Avenue & S Crenshaw Street 6.2 1.33

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Name Type of Basin Location Capacity
(ac-ft)
Footprint
(acre)
Creekside Basin Detention and
layoff recharge
McAuliff Street s/o Mill Creek (E) 89.7 6.59
Doe Avenue Retention Doe Avenue e/o Kelsey Street (S) 5.7 0.68 East Oaks Est. Basin Retention Comstock Street s/o Race Avenue (SE) 5.9 0.65 Emerald Park Subd. Basin Temporary O'Malley Street & Douglas Avenue (NW) 0.2 0.07 Fairview Village Park/Pond Detention N Conyer Street & W Wren Drive 17 3.77 Ferne St. Basin Retention Ferne Street s/o Roosevelt Avenue (NW) 10.9 1.35 Foxwood Estates Basin Retention W Ferguson Avenue & N Roeben Street (SE) 27.5 2.78 Goshen Basin Detention W Goshen Avenue & Camp Drive (SE) 167.7 11.7 Hillsdale Basin Temporary Hillsdale/Marcin 5.4 0.68
Hillsdale/Kelsey Retention Hillsdale Court e/o Kelsey Street 7.8 0.5 Island Oak Basin Detention N St Johns Parkway & E Lark Avenue 1.9 0.79 Kelsey Street Retention N Kelsey Street s/o Roosevelt Avenue 0.9 0.19 Kiwanis Park Basin Detention and
layoff recharge
McAuliff Street & Tulare Avenue (SW) 6.4 0.92
Linwood Ranch Basin Detention Visalia Parkway & S Chinowth Street (NW) 38.1 2.27 McDermott Basin Retention W Mineral King Avenue & S Linwood Avenue 30.6 3.99 Mid State 99 VF Basin Retention Road 76 n/o Ferguson Avenue (NW) 12.4 1.33 Mill Creek Garden Park/Pond Detention Lovers Lane & Mill Creek Parkway (SE) 16.9 4.59 Modoc Basin Retention and
layoff recharge
W Riggin Avenue & N Linwood Street 100 16.07
Mooney Boulevard Basin Detention S Mooney Boulevard & W Cameron Avenue 11.2 1.26 Nevada Street Detention Nevada Street s/o Placer Avenue 6.9 0.92 Oakes Basin Detention and
layoff recharge
E Mineral King Avenue & Road 152 (NW) 61.2 8.55
Oakwest Basin Detention Preston/ Logan 3.4 0.66
Oakwest No. 1 Subd. Basin Detention N Cottonwood Street & Damsen Avenue (SE) 1.8 0.78 Pappas Park/Pond Detention Mineral King Avenue & Chinowth Street (NW) 2.7 0.78 Park Place Basin Retention and
layoff recharge
S Pinkham Street & Victor Avenue 34.6 3.3
Piano Basin Retention Roeben/Goshen 70.2 6.55
Pickett Basin Retention 9755 W Legacy Avenue 6.7 0.72
Pinkham Park/Pond Detention S Pinkham Street & Tulare Avenue (NE) 3.3 0.83 Plaza Drive Detention Plaza Drive s/o Nicholas Avenue 0.81 0.6 Police Station Basin Retention and
layoff recharge
W Cameron Avenue & Woodland Street (SW) 126 12.51
Ridgeview Middle School Temporary Sedona Avenue w/o Road 100 11.8 1.8 Ritchie Industrial Basin Retention N Kelsey Street & W Ferguson Avenue (NE) 20.8 1.89 River Run Ranch Basin Retention1 St Johns Parkway & Madera Street 7.7 0.64

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Name Type of Basin Location Capacity
(ac-ft)
Footprint
(acre)
River Run Ranch Basin (East) Retention St. Johns Parkway & Road 148 (NE) 15.0 1.38 Riverbend Village Park/Pond Detention N Court Street & E Wren Avenue 12 1.95 Road 44/Avenue 280 (NE) Retention and
layoff recharge
Road 44 & Avenue 280 (NE) 393.6 34.05
Road 44/Hume Ave (SE) Retention and
layoff recharge
Road 44 & Hume Avenue (SE) 186.7 33.99
Road 48/Hume Ave (SW) Retention and
layoff recharge
Road 48 & Hume Avenue (SW) 313.1 32.23
Ruiz Park/Pond Detention N Burke Street & Buena Vista Avenue 16.4 5.53 Savannah Foods Basin Detention and
layoff recharge
N Kelsey Street & W Ferguson Avenue (SW) 65.4 10.45
Savannah Heights Basin Retention and
layoff recharge
W Walnut Avenue w/o S Roeben Street 28.6 4.04
Scenic Corridor NE Basin Retention Highway 198 & Shirk Road (NE) 10.7 4.58 Sequoia Heights Subd. Basin Temporary Virmargo Street & Oak Avenue (SE) 4.3 0.52 Seven Oaks Park/Pond Detention S Edison Street & Tulare Avenue 19.9 3.79 Shannon/Modoc Basin Detention and
layoff recharge
Shannon Parkway & N Demaree Street (SE) 117.6 15.5
Shirk Industrial Park Basin Retention Pershing Street w/o Shirk Street (NW) 5.0 0.65 Sierra Village Basin Detention Molenstraat s/o State Route 198 33.6 2.91 Soroptimist Basin Retention N Tipton Street n/o Race Avenue 34.5 4.36 South Cameron Creek Basin Retention W Cameron Avenue & West Street 33.8 3.24 St. Charles Place Subd. Basin Temporary Dunsworth Street s/o Houston (S) 0.8 0.22 Stonebridge Subd. Basin Temporary Cedar Street & Princeton Avenue (E) 0.9 0.31 Stonebridge Subd. Basin Retention Cedar Street & Walnut Avenue (NE) 2.0 1.01 Stonebrook Park/Pond Detention Martin Street & Hemlock Avenue 45.8 8.93 Sunset Park/Pond Retention S Roeben Street & W Lisendra Drive 42.5 5.14 The Ranch Basin Retention Linwood Street & Houston Avenue (SE) 81.8 6.28 U.S. Towers Basin Retention Marcin Street & Paradise Avenue (SW) 2.9 0.51 VECC Temporary School/Murray 14.0 3.32
Webb Estate Basin Detention W Manor Court & W Crowley Court 0.5 0.3 Willow Glen Park/Pond Detention Akers Street & Hurley Avenue (SE) 6.0 2.13 Notes:
e/o - east of; n/o - north of; No. - number; s/o - south of; w/o - west of; NE - northeast; NW - northwest; SE - southeast; SW - southwest.
(1) Sized as Detention Basin.
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Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
S a i n t J o h n s R i v e r
Modoc Ditch
Packwood Creek
Mill Creek
Evans Ditch
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 2.2 Existing Storage Basins

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
Modeled Storage Basin
!² Retention
!² Detention
!² Temporary
Existing Storm Drains
Channel
Storm Water Basin
Railroads
City Limits
County Parcels

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 2-11

2.5 Pump Stations
Pump stations are used throughout the City to move stormwater from storage basins and low-lying drainage areas to receiving facilities where gravity discharge is limited by topography or downstream water levels. Pumping supports system drawdown following storm events and helps manage ponding duration where discharge constraints would otherwise delay basin recovery.

Pump station operations are inherently coupled with downstream receiving conditions, including ditch/canal water surface elevations and allowable stormwater discharge rates. As a result, pump stations should be understood as part of an integrated storage-and-controlled-discharge strategy rather than a standalone “capacity increase” measure. Currently, there are 51 stormwater pumps at 40 locations across the City. The pumps range in capacity from 320 to 13,910 gallons per minute (gpm). Table 2.3 provides a summary of the stormwater pump locations and capacities. Figure 2.3 shows the locations of the pump stations.

Table 2.3 Existing Stormwater Pumps
Pump Location Discharge Capacity
(gpm)
Capacity
(cfs)
Demaree Road & Victor Avenue Demaree Road storm drain to Packwood Creek
9,000 20.05
Chinowth Street near Evans Ditch Evans Ditch 2,600 5.8
County Center Drive near Evans Ditch (1/2) Evans Ditch 2,020 4.5 County Center Drive near Evans Ditch (2/2) Evans Ditch 2,020 4.5 Creekside Basin near McAuliff Street s/o Mill Creek Evans Ditch 4,900 10.92 Pinkham Street near Evans Ditch Evans Ditch 1,400 3.12
Sowell Street near Evans Ditch Evans Ditch 1,400 3.12
Julieann Court near Feemster Avenue Feemster Avenue surface 350 0.78 Soroptimist Basin near N Tipton Street n/o Race Avenue Force main to Mill Creek 5,040 11.23 Locust Street near Oak Avenue Force main to Mill Creek culvert 750 1.67 The Ranch Basin near Linwood Street & Houston Avenue
(SE)
Goshen Avenue storm drain 4,120 9.19
Akers Street near Mill Creek (1/2) Mill Creek 6,780 15.1 Akers Street near Mill Creek (2/2) Mill Creek 5,880 13.1 Chinowth Street near Mill Creek (1/2) Mill Creek 2,500 5.57 Chinowth Street near Mill Creek (2/2) Mill Creek 2,500 5.57 Crenshaw Street near Mill Creek Mill Creek 1,200 2.67
Demaree Road near Mill Creek (1/2) Mill Creek 2,600 5.79 Demaree Road near Mill Creek (2/2) Mill Creek 4,000 8.91 Mill Creek Garden Park/Pond near Lovers Lane & Mill
Creek Parkway (SE)
Mill Creek 1,300 2.89
Mineral King Avenue near Road 86 Mill Creek 380 0.85

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 2-12
Pump Location Discharge Capacity
(gpm)
Capacity
(cfs)
Fairview Village Park/Pond near N Conyer Street & W
Wren Drive
Modoc Ditch 3,400 7.58
Giddings Street near Modoc Ditch Modoc Ditch 400 0.9
Mooney Boulevard near Modoc Ditch (1/2) Modoc Ditch 1,800 4.01 Mooney Boulevard near Modoc Ditch (2/2) Modoc Ditch 1,800 4.01 Riverbend Village Park/Pond near N Court Street & E
Wren Avenue
Modoc Ditch 760 1.69
Shannon/Modoc Basin near Shannon Parkway & N
Demaree Street (SE)
Modoc Ditch 6,600 14.7
Oakwest Basin near Preston/Logan (1/2) North Mill Creek 1,560 3.48 Oakwest Basin near Preston/Logan (2/2) North Mill Creek 1,560 3.48 Goshen Ocean Pump / Goshen Drain North Mill Creek 3,300 7.35 Kiwanis Park near McAuliff Street & Tulare Avenue (SW) Packwood Creek 2,240 5 Mooney Boulevard Basin near Mooney Boulevard &
Cameron Avenue (1/2)
Packwood Creek 13,910 31
Mooney Boulevard Basin near Mooney Boulevard &
Cameron Avenue (2/2)
Packwood Creek 13,910 31
Stonebrook south of Caldwell Avenue near Packwood
Creek (1/2)
Packwood Creek 5,880 13.1
Stonebrook south of Caldwell Avenue near Packwood
Creek (2/2)
Packwood Creek 5,880 13.1
Ben Maddox Way near St. John's River St. John's River 1,400 3.12 Bradley Street near St. John's River (1/2) St. John's River 1,960 4.37 Bradley Street near St. John's River (2/2) St. John's River 1,960 4.37 Buena Vista Avenue near St. John's River (1/2) St. John's River 6,420 14.3 Buena Vista Avenue near St. John's River (2/2) St. John's River 8,000 17.82 Cedar Court near St. John's River St. John's River 5,400 12.03 Combs Park/Pond near S Crenshaw Street & La Vida
Avenue
Storm drain along Akers Street to
Evans Ditch
4,250 9.47
Ben Maddox Way & Houston Avenue Storm drain e/o Ben Maddox Way 2,180 4.85 Ben Maddox Way near E Laura Avenue Storm drain on Ben Maddox Way 1,200 2.67 Caldwell Avenue & Chinowth Street Storm drain on Caldwell Avenue 2,400 5.35 Tulare Avenue near Cotta Street Storm drain on Cotta Street to Packwood Creek
500 1.11
Oakwest No. 1 Subd. Basin near N Cottonwood Street &
Damsen Avenue (SE)
Storm drain on Cottonwood Street to
Mill Creek
320 0.72
Noble Avenue e/o Lovers Lane Storm drain on Noble Avenue 1,800 4.01

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 2-13
Pump Location Discharge Capacity
(gpm)
Capacity
(cfs)
Cherry Meadow Park/Pond near S Pinkham Street &
Cherry Avenue
Storm drain on Pinkham Street to
Packwood Creek
670 1.5
Linwood Ranch Basin near Visalia Parkway & S Chinowth
Street (NW)
Storm drain on Visalia Parkway to
Packwood Creek
4,500 10.03
El Cajon Court near Walnut Avenue Storm drain to Savannah Heights Basin 6,800 15.15 Sierra Village Basin near Molenstraat s/o State Route 198 Watson Ditch 3,800 8.47

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Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
S a i n t J o h n s R i v e r
Modoc Ditch
Packwood Creek
Mill Creek
Evans Ditch
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 2.3 Existing Pump Stations

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
"=) Pump Station
Existing Storm Drains
Channel
Storm Water Basin
Railroads
City Limits
County Parcels

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 2-15

2.6 Storm Drainpipe
The minor drainage system for the City also includes a network of underground storm drains. The pipe ranges in size from 8-inches to 60-inches and is mainly constructed from reinforced concrete. Table 2.4 shows the length of pipe and diameter of the storm drain included in SWMP hydraulic model. Figure 2.4 shows the storm drain currently captured in the City’s GIS system and the storm drain included in the model.

Table 2.4 Storm Drain Pipe Length and Diameter
Diameter (inches) Length (feet)
Circular
8 565
12 11,056
14 88
15 1,529
18 15,955
20 470
21 8,348
24 107,402
27 9,286
30 92,669
36 48,156
42 41,945
48 53,788
54 8,019
60 9,222
Total (feet) 408,499
Total (miles) 77
Force Main
6 1,172
8 626
16 2,299
20 476
Total (feet) 4,573
Total (miles) 1
The City’s GIS storm pipe inventory includes over 290 miles of storm pipe. The SWMP model includes storm pipe of 24-inches in diameter or larger, with some exceptions were smaller diameter storm pipe were included for model connectivity. It is common modeling practice to only include storm pipe of larger diameters due to the cost-benefit of adding the supporting data for all the storm pipe versus the value received from the analysis of all the storm pipe.
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Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
S a i n t J o h n s R i v e r
Modoc Ditch
Packwood Creek
Mill Creek
Evans Ditch
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 2.4 Existing Storm Drain System

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
#* Outfall
"=) Pump Station
Modeled Storage Basin
!² Retention
!² Detention
!² Temporary
Existing Storm Drains
Modeled Storm Drains
Channel
Saint Johns River
Railroads
City Limits
County Parcels
Storm Water Basin

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 2-17

2.7 Ditch and Channel Capacities
The capacity of the City’s major drains is a controlling factor for stormwater discharge and system performance. Major drains may have a physical conveyance capacity that varies by reach condition, vegetation, sediment, and tailwater, and they may also be subject to operational limitations when irrigation deliveries or flood releases occupy channel capacity.

The agreed-upon City capacity based on the ditch and channel use agreements, the 1994 SWMP channel capacities, and the channel capacities calculated during this study are provided in Table 2.5.

Table 2.5 Channel Capacities
Creek Name Agreed City Capacity 1994 SWMP Channel Capacity Updated Channel Capacity Mill Creek N/A 147 to 1,169 cfs 100 to 600 cfs
Packwood Creek N/A 515 to 1,477 cfs 150 to 400 cfs
Evans Ditch 1/2 140 to 277 cfs 50 to 200 cfs
Modoc Ditch 1/3 154 to 674 cfs 50 to 250 cfs
Persian Ditch 1/3 68 to 223 cfs 70 to 230 cfs
Watson Ditch 1/3 131 cfs 130 cfs
Notes:

N/A - not applicable.

The updated capacity ranges differ from the 1994 SWMP because the analyses used different hydraulic methods and definitions of practical channel capacity. Chapter 5 describes the reasons for the differences.

2.8 Ditch and Channel Use Agreements
Stormwater discharge from the City is routed to major drains that are owned and/or operated by irrigation districts and ditch companies. The City has entered into shared-use agreements that define the conditions under which stormwater may be discharged to these facilities. These agreements establish allowable discharge locations and operational constraints during simultaneous-use conditions (such as irrigation deliveries or flood releases that reduce available channel capacity), define maintenance responsibilities within City limits, require controls and coordination for new discharge points, and provide mechanisms for coordination during events when combined flows approach or exceed channel capacity.

For master planning purposes, these agreements are used to define practical discharge constraints and receiving conditions for shared-use waterways. Agreement provisions by facility (Mill Creek, Packwood Creek, Evans Ditch, Modoc Ditch, Persian Ditch, Watson Ditch, and the Tulare Irrigation Canal) are provided in Appendix A.

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 3-1
CHAPTER 3 BASIS OF DESIGN
This chapter summarizes the basis of design used to evaluate the City’s storm drainage system and to develop planning-level recommendations. The basis of design includes:

1. The target level of protection for different elements of the drainage system.

2. The role of LID requirements under the City’s MS4 program.

3. The primary software tools and data sources used for technical analyses.

The City’s storm drainage system consists of both underground storm drains and aboveground conveyance pathways, including streets, swales, and open channels that function as major drains. Because system performance is strongly influenced by the City’s relatively flat topography, the basis of design recognizes that exceedance flows will occur during larger storm events and that overland flow must be considered as part of how the system functions.

3.1 Level of Protection
Stormwater planning typically distinguishes between a minor (collector) drainage system intended to manage frequent storms with tolerable nuisance flooding, and a major drainage system (e.g., principal open channels and waterways) intended to convey larger, less frequent events. The 1994 SWMP established the foundational framework still reflected in City practice: major drains provide the backbone of the system and generally serve drainage areas greater than approximately 100 acres, while minor drains convey runoff from smaller tributary areas to the major system.

A common drainage standard is to provide a system that will limit major damage from a major storm expected to occur once in 50-100 years and to limit nuisance flooding from storm events that would occur on average once in 2-10 years. Excess storm runoff within the City tends to distribute rather than concentrate because of the relatively flat topography. This distribution of flows greatly reduces the threat of major flood damage from local storms. As a result, the intent is to provide a drainage system with the primary purpose of preventing the more frequent nuisance flooding from relatively frequent storms.

3.1.1 Storm Drainage Design Criteria
The City’s day-to-day storm drainage design and development review utilizes the Rational Method. This criterion not only specifies level of protection, but also runoff coefficients and storage volumes to be used during the evaluation.

The City’s current Storm Drainage Design Criteria level of protection is summarized in Table 3.1. The criteria in effect at the time this SWMP was prepared are included in Appendix B. The City is preparing an update to its storm drain standards. Once adopted, the updated standards will supersede the criteria included in Appendix B and should be used for subsequent project design and development review.

STORMWATER MASTER PLAN
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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 3-2
Table 3.1 Storm Drainage Design Criteria Level of Protection Item Level of Protection
Minor (Collector) Drains 2-Years
Major Drains 10-Years
In-Town Detention Basins 10-Years – 10-Days Volume
In-Town Retention Basins 10-Years – 10-Days Volume
Industrial Park Retention Basin 10-Years – 10-Days Volume Downstream Ultimate Storage Basins 10-Days – 50-Years Volume

3.1.2 Stormwater Master Planning Criteria
Criteria and the subsequent evaluation for both the minor drainage system (City internal drainage) and the major drainage system (waterways the City’s internal drainage discharges into) are outlined below.

Two separate approaches were taken for purposes of efficiency and to take advantage of the existing modeling from previous planning efforts; HEC-RAS models for Modoc Ditch, Mill Creek, Evans Ditch, and Packwood Creek were developed through these previous planning efforts.

3.1.2.1 Minor Drainage System
Stormwater master planning generally utilizes more complex modeling software meant to evaluate larger systems and the impacts subparts of each system has on the whole. The minor drainage system is evaluated in USEPA-SWMM version 5.2.4. This software was selected due to its ability to assess complex drainage systems such as that of the City and its cost.

The traditional approach to stormwater master planning is to directly apply the current criteria to the City’s system utilizing standard methods. Because the majority of the City’s system was not designed to the current criteria, this results in numerous deficiencies when the current system is evaluated against it.

Many of these identified deficiencies are not experienced during rain events. Careful thought was taken to understand the best way to evaluate the City’s system as a whole given the design criteria utilized as the City developed. The City conducted a thorough analysis and created the resulting Existing and Future Conditions master planning criteria. Of particular interest was how the resulting master planning model results aligned with the runoff coefficients referenced during design. Iterations were conducted until this condition was satisfied.

The Existing Conditions and Future Conditions criteria are different because the Existing Conditions criteria evaluates the existing infrastructure based on how it was designed, while Future Conditions evaluates the future infrastructure considering the current design criteria. The following criteria are being utilized for this study:
 Existing Conditions Criteria: Three, 2-year, 24-hour storm events spaced 6 days apart. This was developed to generate effective runoff responses consistent with the City’s contemporaneous design basis for much of the existing system.
 Future Conditions Criteria: Three, 2-year, 24-hour storm events spaced 2 days apart. This was developed to produce slightly higher runoff and better match the City’s retention basin sizing and management approach.

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 3-3
The City’s current improvement standard references a 10-year, 10-day total rainfall depth (historically listed as 4.17 inches). However, the City’s runoff coefficients used in Rational Method calculations are calibrated to the 2-year storm intensity, and storage volume calculations based on the Rational Method incorporate rainfall intensity indirectly through those coefficients.

As a result, representing the retention basin criterion in SWMM as a sequence of 2-year-intensity events that sum to approximately the 10-day total depth provides a closer match to how the City’s standards have been applied in practice. Accordingly, the revised design storm approach represents the retention basin total rainfall depth using three 2-year, 24-hour storms (approximately 1.40 inches each) for a total of approximately 4.2 inches, with storm spacing selected to reflect soil drying and recovery behavior in SWMM.

Existing Conditions
To understand if the existing system meets the master planning criteria, the following comparison is completed:
 Junctions:
» Depth of flooding above the rim elevation shall not exceed 0.5 feet. » Hours flooded should be less than the total rainfall duration (72 hours).  Storage Nodes:
» Basins shall have at least 1 foot of freeboard.

Future Conditions
To understand if the future system meets the master planning criteria, the following comparison is completed for any proposed infrastructure:
 Junctions:
» Depth of flooding above the rim elevation shall not exceed 0.5 feet. » Hours flooded should be less than the total rainfall duration (72 hours).  Storage Nodes:
» Basins shall have at least 1 foot of freeboard.
» Basins will utilize the standalone retention basin concept.

3.1.2.2 Major Drainage System
The major drainage system was evaluated in HEC-RAS and the FHWA Hydraulic Toolbox. HEC-RAS is widely used for one-dimensional open-channel hydraulics and enables efficient screening of water surface profiles and capacity constraints along long ditch/creek corridors based on cross-sectional data and structures. The FHWA Hydraulic Toolbox is widely used for the hydraulic evaluation of less complex open-channels conveyance.

The City’s stormwater discharges into the waterways were quantified and the channel capacities determined. The waterways were evaluated on their ability to contain storm flow discharges within their banks.

STORMWATER MASTER PLAN
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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 3-4

3.2 Low Impact Development
LID is a requirement of the City’s MS4 General Permit (Order No. 2013-001-DWQ) and requires applicable development and redevelopment projects to reduce and treat stormwater runoff on or near the project site. In general, projects subject to LID design standards include:
 New development projects on public or private land that fall under the planning and permitting authority of the City.
 Redevelopment projects on public or private land that fall under the planning and permitting authority of the City that result in an increase of more than 50 percent of the impervious surface of the previously existing development.
 Public road projects that create 5,000 square feet or more of newly constructed contiguous impervious surface.
 Linear underground/overhead projects that create 5,000 square feet or more of newly constructed contiguous impervious surface.

LID requirements affect storm drain infrastructure planning in two primary ways:

1. Runoff reduction and flow control for new/redevelopment. To the extent that LID is implemented as required, the volume and peak rate of runoff discharged from new and redevelopment sites to the public system may be reduced relative to traditional development. This can lower incremental demands on downstream pipes and basins for future growth areas.

2. Hydromodification management under MS4. The City’s MS4 program includes hydromodification requirements intended to limit changes in runoff response due to development, including criteria that post-development peak runoff should not exceed pre-development peak runoff for the 2-year, 24-hour storm. This requirement reinforces the City’s long-standing emphasis on managing the more frequent nuisance-flooding events and ties development controls directly to the service level most relevant to minor drainage performance.

LID can be an effective stormwater management approach when applied correctly and should be incorporated where areas are redeveloped or newly developed. Existing developed areas where redevelopment is not anticipated can consider LID, however, more traditional stormwater management techniques such as increased conveyance or storage will likely be more effective. Should LID be incorporated into existing developed areas, this can result in the reduction of some nuisance flooding and can be used to add resilience to the system.

For conservative flood-control planning and to provide a factor of safety, runoff reduction or flow-control benefits attributable to LID were not assumed or credited in the hydrologic modeling or in the sizing of the master-planned storm drainpipes and storage basins. The master-planned facilities were sized using the Future Conditions land-cover and soil assumptions without relying on subdivision- or project-specific LID measures. This approach avoids under sizing regional infrastructure based on measures that may vary by project, location, implementation timing, and long-term maintenance. LID requirements remain applicable to qualifying development and redevelopment projects and should be addressed separately during project-specific design and permitting.

STORMWATER MASTER PLAN
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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 3-5

3.3 Software Programs and Available Data
Table 3.2 describes the major software programs used in this study.

Table 3.2 Software Programs
Program Description
HEC-RAS Version 6.6 Hydraulic model for open channels developed by USACE.

USEPA-SWMM Version 5.2 Dynamic rainfall-runoff simulation model for basin, pumps, and pipe network developed by the USEPA.

AutoCAD 2019 Computer Aided Drafting program by Autodesk Inc.

ArcGIS Version 10. GIS software developed by Esri.

Notes:

ESRI - Environmental Systems Research Institute.

Numerous documents and data were collected and reviewed during the development of the SWMP, as described in Table 3.3.

Table 3.3 Available Data
Data Source
Precipitation NOAA Atlas 14 data.

Soils USDA WSS.

Land Cover USGS NLCD 2019.

Storage City-provided information, including updated stage-storage curves for storage basins missing information in 2005 model.

Pump Stations City-provided information on installed pump horsepower ratings and pump curves as available.

Storm Drain City-provided information, including the 2005 stormwater model and as-built plans as available.

Topographic City-provided LiDAR from 2006.

Previous Studies 1994 SWMP by Boyle Engineering Corporation, 2005 stormwater model developed in Info SWMM, and Packwood Creek hydraulic study.

Notes:

NLCD - National Land Cover Database; USGS - United States Geological Survey; WSS - Web Soil Survey.

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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 4-1
CHAPTER 4 HYDROLOGIC ANALYSIS
Two hydrologic models of the City were developed as part of this SWMP. Models were built to:

1. Reflect the current buildout of the City (existing conditions).

2. Designated future development land uses, including planning areas in the Tier 3 development boundary (future conditions).

This chapter describes the hydrologic methodology used to estimate runoff generated by existing and future development conditions. The chapter also documents the modeling approach, design storm scenarios, subcatchment delineation, rainfall data, infiltration methodology, and hydrologic parameter assumptions used to support the hydraulic analysis described in subsequent chapters.

4.1 Modeling Approach
The City’s stormwater system was evaluated using the USEPA SWMM. Hydrologic inputs were developed at the subcatchment level, and runoff was routed through the storm drain system to downstream facilities and outfalls. Rainfall depth-duration-frequency (DDF) values were derived from NOAA Atlas 14 data, and infiltration (rainfall losses) was computed using the Natural Resources Conservation Service (NRCS) Curve Number (CN) method.

4.1.1 Previous Plan
The 1994 Plan used the kinematic wave overland flow plane runoff computation option in HEC-1. The kinematic wave method represents a subcatchment as an open channel (a very wide, open channel), with inflow to the channel equal to the excess precipitation calculated after the losses are determined through the CN method. This routing method solves the continuity equation along with a simplified form of the momentum equation for both pervious and impervious areas for each timestep. The simplified form of the momentum equations assumes that the slope of the water surface equals the slope of the subcatchment.

Following each timestep the impervious and pervious results are summed to create the runoff volume and peak flow for each subcatchment.

4.1.2 Current Plan
This SWMP uses USEPA-SWMM’s default hydrologic method, the nonlinear reservoir model. In this model, ponded water (runoff greater than the depressional storage) can become runoff outflow. For each timestep, Manning’s equation is used to calculate the runoff volumetric flow rate for both the impervious and pervious areas of the subcatchment assuming the subcatchment is a wide, shallow channel with a slope equal to the slope of the subcatchment. As with the previous method, following each timestep the impervious and pervious results are summed to create the runoff volume and peak flow for each subcatchment.

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4.2 Scenarios
Hydrologic simulations were completed for Existing Conditions (current development and drainage infrastructure) and Future Conditions (General Plan buildout with planned trunk infrastructure).  As described in the previous section, the City developed the following Existing and Future Conditions design storms to be used in this master planning computer modeling:
» Existing Conditions Evaluation Storm: three (3) sequential 2-year, 24-hour storms separated by a 6-day gap.
» Future Conditions / Retention Basin Sizing Storm: three (3) sequential 2-year, 24-hour storms separated by a 2-day gap.

4.3 Subcatchment Delineation
Hydrologic parameters were calculated at the subcatchment level. Subcatchments are unique areas of land that discharge to the same location. The Existing Conditions model has 708 subcatchments and the Future Conditions model contains 881 subcatchments. Subcatchments were delineated primarily based on the storm drain network, with future subcatchments expanded/edited to represent planned growth and proposed stormwater infrastructure (trunk, retention facilities, and pump facilities).

The Existing Conditions subcatchments are shown in Figure 4.1, and the Future Conditions subcatchments are shown in Figure 4.2.

Please note, some catchments within the northwest portion of the system only required modeling of street surfaces since industrial-zoned properties are required to contain all stormwater from the property onsite.

Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
Last Revised: August 10, 2026 [ENTER PROJECT WISE PATH NAME TO MXD] For Example:pw://Carollo/Documents/Client/CA/ClientName/10265A00/Data/GIS/Figure_01_01.aprx O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
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Figure 4.1 Existing Conditions Model Subcatchments

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
Subcatchments
City Limits
Railroads
County Parcels
Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
Last Revised: August 13, 2026 [ENTER PROJECT WISE PATH NAME TO MXD] For Example:pw://Carollo/Documents/Client/CA/ClientName/10265A00/Data/GIS/Figure_01_01.aprx O
0 5,0002,500
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

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Figure 4.2 Future Conditions Model Subcatchments

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
Subcatchments
City Limits
Railroads
County Parcels
Public Urban Development
Growth Tiers
Urban Development
Boundary Tier 1
Urban Development
Boundary Tier 2
Urban Growth Boundary
Tier 3

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4.4 Rainfall Data
The precipitation DDF values reported in the 1994 SWMP are summarized in Table 4.1 for historical comparison. These values were developed from the Exeter station, the closest continuous recording gage to the City.

To represent Visalia, the short-duration (5 minutes to 1 day) Exeter station data was reduced by 10 percent, and the long-duration values were developed from the standard gage rainfall data collected manually in Visalia.

Table 4.1 Precipitation Depth-Duration-Frequency from 1994 SWMP Duration 2 Years (inches) 5 Years (inches) 10 Years (inches) 25 Years (inches) 50 Years (inches) 5 minutes 0.14 0.18 0.22 0.26 0.29
10 minutes 0.18 0.24 0.29 0.34 0.39
15 minutes 0.20 0.27 0.32 0.39 0.43
30 minutes 0.24 0.34 0.40 0.48 0.53
1 hours 0.34 0.47 0.56 0.67 0.74
2 hours 0.50 0.68 0.80 0.96 1.07
3 hours 0.60 0.83 0.98 1.18 1.31
6 hours 0.78 1.08 1.28 1.53 1.71
12 hours 1.03 1.42 1.68 2.01 2.24
1 day 1.28 1.76 2.09 2.48 2.77
2 days 1.55 2.20 2.64 3.19 3.59
5 days 1.98 2.87 3.48 4.24 4.79
10 days 2.41 3.47 4.17 5.04 5.67
The DDF values were updated using NOAA Atlas 14, Volume 6, Version 2, and these updated values are summarized in Table 4.2. The data from the updated NOAA Atlas 14 shows that rainfall depths have decreased slightly for most durations and frequencies from the data used in 1994 SWMP.

Table 4.2 Current Precipitation Depth-Duration-Frequency Duration 2-Years
(inches)
5-Years
(inches)
10-Years
(inches)
25-Years
(inches)
50-Years
(inches)
100-Years
(inches)
5 minutes 0.10 0.12 0.15 0.20 0.24 0.29
10 minutes 0.14 0.18 0.22 0.28 0.34 0.41
15 minutes 0.16 0.22 0.26 0.34 0.41 0.50
30 minutes 0.23 0.30 0.36 0.47 0.57 0.68
1 hour 0.31 0.40 0.49 0.64 0.77 0.93
2 hours 0.45 0.57 0.69 0.87 1.0 1.2
3 hours 0.56 0.71 0.84 1.1 1.2 1.5
6 hours 0.78 0.98 1.2 1.4 1.7 2.0
12 hours 1.1 1.4 1.6 2.1 2.4 2.8

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Duration 2-Years
(inches)
5-Years
(inches)
10-Years
(inches)
25-Years
(inches)
50-Years
(inches)
100-Years
(inches)
1 day 1.4 1.9 2.3 2.9 3.4 3.9
2 days 1.7 2.2 2.7 3.4 4.0 4.6
3 days 1.9 2.5 3.0 3.7 4.4 5.1
4 days 2.1 2.7 3.2 4.0 4.7 5.4
7 days 2.4 3.1 3.7 4.6 5.3 6.1
10 days 2.7 3.4 4.1 5.0 5.7 6.5
NOAA Atlas 14 DDF estimates are the basis for the rainfall depths used to develop design storm hyetographs for SWMM evaluation. This master plan applies a single representative set of Atlas 14 values across the City to maintain consistency in design criteria and interpretation of system performance.

This approach mirrors the intent of a master plan-level standard: uniform application of design rainfall assumptions across the planning area.

The location information for the representative extraction point is as follows:
 Name: Visalia, California, USA (Source: ESRI Maps).
 Latitude: 36.3283°
 Longitude: -119.2992°
 Elevation: 329 feet (Source: USGS).

For final design and project-specific analysis, site-specific Atlas 14 values (and locally appropriate temporal distributions) are applied at the project location to refine design storms and confirm final sizing.

4.5 Infiltration
Infiltration (rainfall losses) was simulated using the NRCS CN method in USEPA-SWMM. This methodology utilizes the current land cover (impervious versus pervious) and the hydrologic soil group (HSG). In general, the lower the CN, the more infiltration that can occur.

The CN is made up of the amount of pervious and impervious land cover and the HSG. The more pervious a land cover, the more infiltration that can occur. HSGs range from A (sand/gravel) to D (clay); the more sand/gravel in a soil type, the more infiltration that can occur.

4.5.1 Existing Conditions
CNs were generated using land cover and impervious data from NLCD 2019 and HSG data referenced from the USDA WSS. A weighted average CN was calculated by determining the area of each land use and HSG within each subcatchment. A single composite CN was developed for each subcatchment. This process was facilitated by using spatial analysis techniques within GIS software.

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MASTER PLANS AND FINANCIAL NEXUS STUDY 4-7
Table 4.3 shows the CN for each land cover type for the corresponding HSG utilized for this study.

Table 4.3 Composite Curve Numbers for specific HSG and NLCD Landcover NLCD Landcover Type HSG A HSG B HSG C HSG D
Open Water 100 100 100 100
Perennial Ice/Snow 40 40 40 40
Developed, Open Space 52 68 78 84
Developed, Low Intensity 81 88 90 93
Developed, Medium Intensity 84 89 93 94
Developed High Intensity 88 92 93 94
Barren Land (Rock/Sand/Clay) 70 81 88 92
Deciduous Forest 32 48 57 63
Evergreen Forest 39 58 73 80
Mixed Forest 46 60 68 74
Shrub/Scrub 40 42 55 62
Grassland/Herbaceous Arid 40 63 75 85
Pasture/Hay Fair 40 61 73 79
Cultivated Crops 62 74 82 86
Woody Wetlands 86 86 86 86
Emergent Herbaceous Wetlands 80 80 80 80
Development density has varying definitions depending upon the source of the data. NLCD includes the following definitions for developed areas:
 Developed, Open Space: areas with a mixture of some constructed materials, but mostly vegetation in the form of lawn grasses. Impervious surfaces account for less than 20 percent of total cover. These areas most commonly include large-lot single-family housing units, parks, golf courses, and vegetation planted in developed settings for recreation, erosion control, or aesthetic purposes.  Developed, Low Intensity: areas with a mixture of constructed materials and vegetation. Impervious surfaces account for 20 percent to 49 percent of total cover. These areas most commonly include single-family housing units.
 Developed, Medium Intensity: areas with a mixture of constructed materials and vegetation.

Impervious surfaces account for 50 percent to 79 percent of the total cover. These areas most commonly include single-family housing units.
 Developed High Intensity: highly developed areas where people reside or work in high numbers.

Examples include apartment complexes, row houses and commercial/industrial. Impervious surfaces account for 80 percent to 100 percent of the total cover.

While NLCD 2019 offers a consistent regional dataset, it does not always precisely reflect current site-specific conditions required for municipal drainage modeling, particularly in areas experiencing recent development, redevelopment, or where open space and low-intensity development may be misclassified.

To more accurately represent present land use, the NLCD-based land cover layer was compared to the latest available aerial imagery and updated wherever differences were identified. Instances of discrepancy,

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such as newly developed residential areas, modifications in commercial zones, or conversions from open space to residential or industrial uses, were corrected through manual edits to the NLCD layer based on observed conditions. This validation process helped ensure the land cover data supporting drainage modeling accurately depicted the contemporary landscape, thereby minimizing potential errors in runoff calculations and enhancing model reliability. This methodology is helpful for municipal planning because it incorporates local changes that regional datasets may overlook, including small-scale development, recent construction activity, and shifts in land management practices.

Additionally, this SWMP reflects updated soil survey mapping. In the 1994 master plan, the USDA mapping characterized the dominant mapped soils as HSG C, while the updated USDA WSS mapping indicates the dominant soil type is HSG B in much of the City.

Figure 4.3 shows the HSGs. Figure 4.4 shows the 2019 existing conditions NLCD land cover in Visalia.

4.5.2 Future Conditions
Future Conditions CNs were developed using General Plan land uses, known future development information, updated future drainage areas, and the same HSG data used for the Existing Conditions model. Future land cover assumptions were applied to represent planned buildout within the Tier 3 UGB and other future growth areas included in the model.

Composite CNs were calculated for each Future Conditions subcatchment based on the weighted combination of future land cover and mapped HSG. Where more specific development information was available, future land cover assumptions were refined to better represent the anticipated drainage condition. This approach provides a consistent runoff basis for evaluating future trunk conveyance, storage basin sizing, and FCIPs. Figure 4.5 shows the 2030 General Plan Land Use and future known developments.

4.6 Subcatchment Width
The width parameter affects how quickly runoff is produced in each subcatchment. The longer the width, the less precipitation is stored, and therefore the runoff hydrograph rises and falls more quickly.

The width for each subcatchment in both Existing and Future Conditions was calculated by dividing the subcatchment area by the overland flow path length. Overland flow path lengths were measured for approximately 5 percent of the subcatchments with varying land covers and used to estimate the lengths for similar subcatchments. In general, residential area flow paths averaged 125 feet, undeveloped fields and park areas averaged 500 feet, and highly developed urban areas measured less than 100 feet.

For Future Conditions subcatchments created or modified as part of the future drainage network and FCIP development, width values were assigned using the same methodology applied to the Existing Conditions model. Where proposed subcatchments represent future development areas or revised tributary areas to planned trunk infrastructure, overland flow path assumptions were reviewed for consistency with the anticipated drainage pattern, land use, and modeled outlet location.

Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
Modoc Ditch
Packwood Creek
Mill Creek
Evans Ditch
S a i n t J o h n s R i v e r
Last Revised: August 10, 2026 [ENTER PROJECT WISE PATH NAME TO MXD] For Example:pw://Carollo/Documents/Client/CA/ClientName/10265A00/Data/GIS/Figure_01_01.aprx O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

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Figure 4.3 Hydrologic Soil Groups

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
Hydrologic Soil Group
Group A
Group B
Group C
Group D
Channel
Saint Johns River
City Limits
County Parcels
Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
S a i n t J o h n s R i v e r
Modoc Ditch
Packwood Creek
Mill Creek
Evans Ditch
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: City of Visalia, USGS
ESRI, National Land Cover Dataset

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Figure 4.4 Existing Conditions Land Cover

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
City Limits
Channel
Saint Johns River
Land Cover
Open Water
Perennial Ice/Snow
Developed, Open Space
Developed, Low
Intensity
Developed, Medium
Intensity
Developed High
Intensity
Barren Land (Rock/
Sand/Clay)
Deciduous Forest
Evergreen Forest
Mixed Forest
Shrub/Scrub
Grassland/Herbaceous
Arid
Pasture/Hay Fair
Cultivated Crops
Woody Wetlands
Emergent Herbaceous
Wetlands
Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
Saint Johns River
Modoc Ditch
Packwood Creek
Mill Creek
Evans Ditch
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet Disclaimer: Features shown in this figure are for planning purposes and represent approximate locations. Engineering and/or survey accuracy is not implied.Data Sources: City of Visalia, USGS
ESRI, National Land Cover Dataset

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Figure 4.5 2030 General Plan Land Use

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
City Limits
Saint Johns River
Channel
County Parcels
Public Urban Development
Growth Tiers
Urban Development
Boundary Tier 1
Urban Development
Boundary Tier 2
Urban Growth Boundary
Tier 3
General Plan Land Use
Agriculture
Business Research Park
Conservation
Commercial Mixed Use
Commercial
Neighborhood
Commercial Regional
Commercial Service
Downtown Mixed Use
Industrial
Light Industrial
Office
Public Institutional
Parks/Recreation
Reserve
Residential High Density
Residential Low Density
Residential Medium
Density
Residential Very Low
Density

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4.7 Subcatchment Slope
The slope for each subcatchment in both Existing and Future Conditions was calculated by rasterizing the topographic data provided by the City and calculating zonal statistics by subcatchment using spatial analysis techniques. Subcatchment slopes varied from 0 percent to 4.2 percent, with 95 percent of the subcatchments having a slope less than 1 percent.

Subcatchment slope was confirmed and refined because it directly influences runoff timing and peak rate in USEPA-SWMM. In areas of low relief where GIS-derived slopes can be near-zero due to terrain resolution limitations, zero-slope subcatchments were corrected to representative slopes that reflect the expected drainage behavior. Representative slopes were selected based on adjacent topographic context and drainage characteristics, and slope refinements were applied consistently to maintain stable runoff routing and realistic hydrograph timing.

For Future Conditions subcatchments created or modified as part of future drainage network and FCIP development, slopes were reviewed for consistency with the anticipated future drainage pattern and modeled outlet location. Where proposed subcatchments represent future development areas, final project design should confirm slopes using detailed grading plans and survey data.

4.8 Percent Imperviousness
Percent imperviousness within the subcatchments was set to 0 percent for all subcatchments. This is due to using the CN approach for the infiltration method.

The CN infiltration method incorporates the impervious area into the CNs. In USEPA-SWMM any defined impervious area is routed directly to the subcatchment outlet. Therefore, if the percent imperviousness of the subcatchment was also entered, it would result in double-counting the runoff-response of the impervious areas.

4.9 Subcatchment Subareas
Subcatchment subarea parameters were updated to be consistent with CN Infiltration Method as discussed in the SWMM Reference Manual, Volume 1-Hydrology (Revised).

Combined, these subarea settings ensure that: (1) runoff initiation and abstraction are represented through CN-derived initial abstraction; (2) runoff volume is controlled by CN infiltration/loss behavior; and (3) runoff timing is controlled primarily through subcatchment geometry and slope, providing a consistent basis for comparing results across subcatchments and between existing and future conditions.

4.9.1 Pervious Depression Storage (Initial Abstraction) Pervious depression storage was set equal to the initial abstraction depth associated with each subcatchment’s CN value. Initial abstraction was computed as:

IA = 0.2S,
where S = (1,000/CN) − 10
Because CN varies by subcatchment, depression storage values were assigned on a subcatchment-specific basis rather than using a single uniform value model-wide. This update ensures that the onset of runoff and rainfall losses are represented consistently with the CN framework.

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4.9.2 Pervious Surface Roughness (Manning’s n)
Pervious Manning’s n within subarea routing was set to 0. This setting avoids introducing additional runoff delay inside the subcatchment that would otherwise compound with timing already represented through subcatchment geometry (width) and slope under the nonlinear reservoir method. With this configuration, hydrograph timing is controlled primarily by geometry and slope assumptions rather than internal subarea routing friction.

4.9.3 Subarea Routing
Subarea routing was set so that runoff is routed directly to the subcatchment outlet. This simplification reduces internal routing complexity and avoids unnecessary alteration of hydrograph timing while maintaining the intended loss representation.

Tables summarizing the existing conditions hydrologic parameters can be found in Appendix C. Future conditions hydrologic parameters for each subcatchment can be found in Appendix D.

4.10 Assumptions and Limitations
The following assumptions and limitations apply to this section:

1. While Atlas 14 estimates can vary across the City, that variability is not expected to materially change the master plan’s planning-level conclusions when a single consistent set of rainfall depths is applied across all models and alternatives. The master plan is intended to support comparative evaluation, identifying relative system constraints, screening improvement concepts, and prioritizing capital projects.

2. Using one consistent Atlas 14 dataset ensures that differences in predicted flooding, surcharge, and conveyance performance are driven by system hydraulics and proposed improvements (not by shifting rainfall inputs across locations). Any spatial variation in Atlas 14 depths would primarily scale results up or down slightly, but it would not be expected to change the overall identification of major problem areas or the relative ranking of improvement options at the planning level.

3. Because HSG B generally represents greater infiltration potential than HSG C, use of the updated USDA WSS mapping can reduce runoff estimates relative to the 1994 soil assumptions where land cover and drainage configuration are otherwise similar. This effect is accounted for through the composite CN calculation. However, future development, increased imperviousness, and changes in drainage connectivity can offset or exceed the reduced runoff potential associated with more permeable mapped soils. Therefore, Future Conditions hydrologic results should be interpreted as the combined effect of future land cover, mapped soil conditions, subcatchment routing assumptions, and proposed drainage infrastructure.

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MASTER PLANS AND FINANCIAL NEXUS STUDY 4-14

4. The Future Conditions hydrologic model represents planning-level buildout conditions based on General Plan land uses, known future development information, and proposed FCIPs available at the time of this SWMP update. The curve number selected for each land use represents the average planned density of that land use. Future land use changes, more dense development within a land use category, revised development plans, or changes to City design criteria may require future model updates or revisions to the future conditions proposed solutions. Where a future drainage area contains distinct concentrations of planned land uses that materially affect runoff generation or routing, those areas may be represented as separate subcatchments while retaining the same General Plan- and HSG-based CN methodology, as applied for FCIP No. 13.

5. Future subcatchment boundaries are planning-level drainage areas developed to represent anticipated tributary areas to proposed trunk storm drains, storage basins, and outfalls. Final project design should confirm drainage boundaries using detailed grading plans, survey data, and site-specific development layouts.

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CHAPTER 5 HYDRAULIC ANALYSIS OF WATERWAYS
This chapter summarizes the planning-level hydraulic evaluation of the City’s primary stormwater receiving waterways (Modoc Ditch, Mill Creek, Evans Ditch, and Packwood Creek) and compares modeled stormwater discharges to available information on historic conveyance.

5.1 Waterway Overview
The City’s receiving waterways are largely irrigation conveyances. They are operated under shared-use conditions that can constrain the timing and quantity of stormwater discharge into them, particularly when irrigation or Kaweah-related releases are present. The waterways are described in Chapter 2.

5.2 Modeling Approach
Modeling and analysis of the City’s waterways was performed. The City’s stormwater discharges into the waterways were quantified and the channel capacities determined.

Cross-section geometry and representations of roadway crossings/inline structures were utilized to understand the available capacity in the waterways. The waterways were then evaluated on their ability to contain storm flow discharges within their banks.

HEC-RAS was retained for the principal waterways because the available models represent long open-channel corridors using detailed cross sections, roadway crossings, inline structures, and water-surface profiles. This format is well suited to screening where and at what steady-flow magnitude channel banks may be overtopped. Maintaining the separate models (HEC-RAS versus USEPA-SWMM) allowed the study to use the previously developed waterway geometry without reconstructing the full channel corridors in SWMM.

The analysis includes basins that are linked to the waterways that provide off-stream regulation and storage of peak flows. Capturing and retaining stormwater discharges in off-stream storage basins can maintain channel capacity for peak flows downstream.

HEC-RAS models were built for Modoc Ditch, Mill Creek, Evans Ditch, and Packwood Creek.

The HEC-RAS models were built using the City-provided topographic data. In some locations ponded water or vegetation hindered the accuracy of the LiDAR data; the topographic data was adjusted in these areas. Manning’s n roughness values were assigned as 0.022 for the earthen channels, 0.033 for rock-lined areas, and 0.015 for culverts.

Additional waterways were analyzed using the FHWA Hydraulic Toolbox software and include North Mill Creek and Persian/Watson Ditches.

The modeled ditches and creeks are shown in Figure 5.1.

Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
S a i n t J o h n s R i v e r
Modoc Ditch
Packwood Creek
Mill Creek
Evans Ditch
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 5.1 HEC-RAS Modeled Reaches

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
Saint Johns River
Modeled Reaches
Evans Ditch
Mill Creek
Modoc Ditch
Packwood Creek
Railroads
City Limits
County Parcels

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 5-3

5.3 Major Drainage System Inflows
The locations of existing outfalls, including pumped flows, and storage basins along each of the channels were considered in the analysis. A summary of the number of modeled outfalls, outfalls that are pumped flows, and storage basins located in proximity to each channel is provided in Table 5.1. Figure 5.2 shows the locations for Modoc Ditch, Figure 5.3 shows the locations for Mill Creek, Figure 5.4 shows the locations for Evans Ditch, and Figure 5.5 shows the locations for Packwood Creek.

Table 5.1 Outfalls and Storage Basins along Waterways
Waterway Total Modeled Outfalls Outfalls with Pumped Flows Storage Basins Modoc Ditch 16 6 6
Mill Creek 37 12 10
Evans Ditch 10 7 3
Packwood Creek 37 9 9
Both pumped and gravity discharges from the storm drain system enter the ditches and creeks. To understand the inflows into the waterways, the peak flows from the outfalls from the minor drainage system along each ditch and creek were calculated for the Existing Conditions and Future Conditions storm events.

For each waterway, the modeled gravity and pumped outfall discharges were summed at each SWMM reporting timestep, and the maximum combined value was selected as a planning-level screening flow.

Because the outfalls are distributed along each waterway, the summed peak does not represent a single measured or modeled flow at one cross-section. It is used to compare the general magnitude of City stormwater discharges with the planning-level waterway capacity ranges. This evaluation was conducted for both Existing and Future Conditions. The selected peak flow values from the Existing Conditions are summarized in Table 5.2. The maximum historic flow for each waterway is also included in the table.

Table 5.2 Existing Conditions Stormwater Outfall Peak Flows Waterway Maximum Historic Flow (2000-2019) (cfs) Existing Conditions (cfs) Modoc Ditch 86 120
Mill Creek 169 600
Evans Ditch 50 100
Packwood Creek 300 320
The modeled values are not directly comparable with the historic maximums because the historic values represent observed operational flows, whereas the modeled values are summed planning-level outfall peaks under the specified design storm. The values are used as screening inputs for the waterway evaluation described in Section 5.4.
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Rd 68
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Camp Dr
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0 2,5001,250
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 5.2 Modoc Ditch Outfalls and Nearby Storage Basins

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
#* Modoc Ditch Outfalls
"=) Pump Station
Modeled Storage Basin
!² Retention
!² Detention
!² Temporary
Modoc Ditch
Existing Storm Drains
Saint Johns River
Storm Water Basin
Railroads
City Limits
County Parcels
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W Riggin Ave
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N Akers St
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Mill Creek
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0 5,0002,500
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 5.3 Mill Creek Outfalls and Nearby Storage Basins

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
#* Mill Creek Outfalls
"=) Pump Station
Modeled Storage Basin
!² Retention
!² Detention
!² Temporary
Mill Creek
Existing Storm Drains
Saint Johns River
Railroads
City Limits
County Parcels
Storm Water Basin
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W Walnut Ave
S Linwood St
W Houston Ave
E Main St
S County Center Dr
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N Lovers Lane
W Noble Ave
W Goshen Ave
S Ben Maddox Way
S Mc Auliff St
W Tulare Ave
S Mooney Blvd
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Hwy 198
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E N o b l e A v e
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E Goshen Ave
S Burke St
E C a l d w e l l A v e
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Rd 148
Ave 276
Evans Ditch
Evans Ditch
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 2,0001,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 5.4 Evans Ditch Outfalls and Nearby Storage Basins

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
#* Evans Ditch Outfalls
"=) Pump Station
Modeled Storage Basin
!² Retention
!² Detention
!² Temporary
Evans Ditch
Existing Storm Drains
Saint Johns River
Railroads
City Limits
County Parcels
Storm Water Basin
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Rd 140
Ave 272
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W Myrtle Ave
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E Main St
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W Goshen Ave
S Ben Maddox Way
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Rd 148
W Tulare Ave
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W Mineral King Ave
E Houston Ave
E Noble Ave
Ave 272
W M i n e r a l K i n g A v e
W Noble Ave
W V i s a l i a P k w y
E Goshen Ave
S Burke St
E C a l d w e l l A v e
S Mooney Blvd
Rd 156
Rd 152
Ave 280
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Packwood Creek
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 2,0001,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 5.5 Packwood Creek Outfalls and Nearby Storage Basins

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
#*
Packwood Creek
Outfalls
"=) Pump Station
Modeled Storage Basin
!² Retention
!² Detention
!² Temporary
Packwood Creek
Existing Storm Drains
Railroads
City Limits
County Parcels
Storm Water Basin

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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 5-8
Future Conditions inflows to the major drainage system were evaluated using the final Future Conditions SWMM model with proposed FCIPs included. The modeled Future Conditions outfall flows include gravity and pumped discharges from the future storm drain system to the City’s receiving waterways.

The Future Conditions outfall flows were used to evaluate how planned development and proposed improvements may change discharges to Modoc Ditch, Mill Creek, Evans Ditch, and Packwood Creek. The flow values are planning-level values and are intended to support comparison of future discharge conditions to available waterway capacity information.

The peak flows summarized in Table 5.3 represent the maximum modeled outfall discharge to each waterway during the Future Conditions design storm.

Table 5.3 Future Conditions Stormwater Outfall Peak Flows Waterway Maximum Historic Flow (2000-2019) (cfs) Future Conditions (cfs) Modoc Ditch 86 150
Mill Creek 169 1,140
Evans Ditch 50 140
Packwood Creek 300 1,060
The Future Conditions peak flow value shown in Table 5.3 are higher than the Existing Conditions peak flow values shown in Table 5.2. There are three main reasons for this:

1. The design storms used for Existing Conditions and Future Conditions are different. The Future Conditions storm provides less recovery time between events and therefore generates more runoff.

2. The additional, projected, future development is included in Future Conditions. Because future development will likely result in more impervious areas and more efficient conveyance systems, the peak flows are expected to increase.

3. The Future Conditions values represent the maximum combined discharge from all modeled gravity and pumped outfalls, including existing developed areas, existing and proposed drainage facilities, controlled basin releases, and revised tributary routing.

Modeling indicates the proposed retention basins reduce or eliminate downstream discharge from the areas discharging to them. Table 5.3 represents the overall system response under the Future Conditions design storm.

5.4 Channel Capacity Analysis
Once the peak discharges to the channels were calculated, the channel capacities were evaluated.

Channel capacities were determined differently based on if the channel is evaluated in HEC-RAS or the FHWA Hydraulic Toolbox.

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5.4.1 HEC-RAS
HEC-RAS steady-flow models were used to evaluate the planning-level capacity of Modoc Ditch, Mill Creek, Evans Ditch, and Packwood Creek. These simulations are hydraulic capacity-screening runs and are not independently assigned a storm recurrence interval.

Steady flow files were created for each waterway. Table 5.4 shows the values used in the steady flow files including summed peak flow outfall flow from the previous section, the low end of the range, and the high end of the range. Table 5.4 identifies the profile corresponding to the summed Existing Conditions peak outfall flow described in Section 5.3, together with the profiles selected as the lower and upper ends of the reported planning-level capacity range.

Table 5.4 Steady-Flow Profile Values
Waterway Existing Conditions (cfs) Low End of Range (cfs) High End of Range (cfs) Modoc Ditch 120 50 250
Mill Creek 600 100 600
Evans Ditch 100 50 200
Packwood Creek 320 150 400
The low end of the range identifies the flow rates at which channel-bank overtopping begin for any cross section long the waterway. The high end of the range identifies where the last cross sections begin to overtop. The high end represents conditions where overtopping occurs at a majority of the modeled cross sections.

5.4.2 Federal Highway Administration Hydraulic Toolbox
For North Mill Creek and the Persian/Watson Ditches, the FHWA Hydraulic Toolbox was used. Flow rates were iterated until overtopping began.

5.5 Channel Capacity Results
The HEC-RAS modeling analysis results for the Modoc Ditch, Mill Creek, Evans Ditch, and Packwood Creek are presented in the following subsections. The Hydraulic Toolbox results are also included for North Mill Creek and Persian/Watson Ditches.

For each section, the results from the 1994 SWMP are included for ease of comparison. It is important to note that the 1994 SWMP used a simplified Manning’s equation analysis based on a Manning’s n value of

0.030 and a slope of 0.001. This is a different hydraulic approach for this study where a more detailed planning-level HEC-RAS model and the FHWA Hydraulic Toolbox are used.

5.5.1 Modoc Ditch
Modoc Ditch was modeled as three segments. The first segment starts upstream at the divergence from St. John’s River, ends at the split at Riggin Avenue, and is 13,275 feet long. The second segment continues from Riggin Avenue northwestward across the City and is 32,755 feet long. The third segment continues from the split along Riggin Avenue and is 3,540 feet long.

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There are 1,012 cross sections spaced approximately every 50 feet along the three segments, and 31 roadway crossings and four inline structures modeled. Survey data was unavailable for the culverts, and therefore invert elevations and slopes were estimated based on the topography and may not represent observed field conditions.

The 1994 SWMP estimated the capacity of Modoc Ditch to range from 154 to 674 cfs. The HEC-RAS steady-flow results produced an updated range of approximately 50 to 250 cfs.

Bank overtopping was observed upstream of culverts and roadway crossings, and further study may be necessary to determine if undersized culverts are present and need to be upsized for additional capacity in Modoc Ditch.

The lower updated range primarily reflects the more detailed representation of channel geometry, backwater, and localized hydraulic controls that were not represented in the simplified 1994 analysis; it does not, by itself, demonstrate that the physical capacity of the ditch has declined since 1994.

Because field survey information was unavailable for the culverts and some invert elevations and slopes were estimated from available topography, additional survey and hydraulic evaluation would be required before recommending improvements to specific crossings.

5.5.2 Mill Creek
Mill Creek was modeled as nine segments, which were split by culverts longer than 200 feet that were unable to be modeled correctly in HEC-RAS due to model computation constraints. The nine segments, in total, are 68,125 feet long.

There are 1,404 cross sections spaced approximately every 50 feet along the nine segments, with 55 roadway crossings and two inline structures modeled. Survey data was unavailable for most of the modeled culverts, and therefore invert elevations and slopes were estimated based on the topography and may not represent observed field conditions.

The 1994 SWMP determined the channel capacity ranges from 147 to 1,169 cfs, while this study found the range to be 100 to 600 cfs.

The main channel capacity bottleneck sections are in the City. There are significant channel expansion constraints, especially through the established residential areas between Mooney and Akers Streets.

The highest capacities were observed between the split with Kaweah River and split with Evans Ditch. Bank overtopping was observed upstream of culverts and roadway crossings, and further study may be necessary to determine if undersized culverts are present and need to be upsized for additional capacity in Mill Creek.

5.5.3 Evans Ditch
Evans Ditch was modeled as four segments, which were split by culverts longer than 200 feet that were unable to be modeled correctly in HEC-RAS due to computational model constraints. The four segments, in total, are 34,200 feet long.

There are 695 cross sections spaced approximately every 50 feet along the four segments, with 33 roadway crossings and one inline structure modeled. Survey data was unavailable for most of the

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culverts, and therefore invert elevations and slopes were estimated based on the topography and may not represent observed field conditions.

The 1994 SWMP estimated the capacity of Evans Ditch to range from 140 to 277 cfs. The HEC-RAS steady-flow results produced an updated range of approximately 50 to 200 cfs. The highest capacity was observed in the downstream segment along Caldwell Avenue.

The lower updated range reflects the more detailed representation of channel geometry, roadway crossings, backwater, and localized hydraulic controls and does not necessarily indicate that the physical capacity of Evans Ditch has decreased since 1994.

There are limited expansion capabilities because most of the land along the channel is developed within the City limits.

5.5.4 Packwood Creek
Packwood Creek is modeled as one reach that is 42,740 feet long.

There are 197 cross sections spaced approximately every 200 feet along the reach, with 24 roadway crossings and six inline structures modeled. Survey data was unavailable for some of the culverts, and therefore invert elevations and slopes were estimated based on the topography and may not represent observed field conditions.

The 1994 SWMP estimated the capacity of Packwood Creek to range from 515 to 1,477 cfs. The HEC-RAS steady-flow results produced an updated range of approximately 150 to 400 cfs. The highest capacity was observed near Road 128.

The lower updated range primarily reflects the more detailed representation of channel geometry and localized hydraulic controls and does not necessarily indicate that the physical capacity of Packwood Creek has decreased since 1994.

Survey information was unavailable for some culverts; therefore, their invert elevations and slopes were estimated from available topographic information, and additional field survey and hydraulic analysis would be needed to confirm the capacity of specific crossings.

5.5.5 North Mill Creek
North Mill Creek mainly functions to divert high flows from Mill Creek when capacity has been reached.

FHWA Hydraulic Toolbox software was used to estimate the maximum flow in North Mill Creek to be approximately 200 cfs.

5.5.6 Persian/Watson Ditches
The Persian/Watson Ditches are irrigation conveyance facilities that, as a secondary function, provide a stormwater and high-flow diversion function from Mill Creek when capacity is reached. The system includes one main channel and four bifurcated channels. FHWA Hydraulic Toolbox software was used to confirm the flow ranges in the five channels that were specified in the 1994 SWMP.

Channel capacity varies from 70 to 230 cfs. According to the 1994 SWMP, the maximum flood flow at the headgate is approximately 97 cfs, and the maximum winter entitlement flow is 99 cfs.

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There is potential to expand the channel since the adjacent land is mostly undeveloped.

Table 5.5 shows the estimated flow capacity for the Persian/Watson Ditches.

Table 5.5 Persian/Watson Ditches
Channel Estimated Flow Capacity (cfs)
Persian-Watson Ditch 120-230
North Fork Persian Ditch 100
Middle Fork Persian Ditch 70
Watson Ditch 130
Watson/South Branch Persian Ditch 150
Table 5.6 summarizes the estimated flow capacity for the waterways and includes the historic maximum flow.

Table 5.6 Estimated Flow Capacity for the Waterways and the Historic Maximum Flow Waterway Maximum Historic Flow
(2000-2019) (cfs)
1994 SWMP Range 2026 SWMP Range
Modoc Ditch 86 154-674 50-250
Mill Creek 169 147-1,169 100-600
Evans Ditch 50 140-277 50-200
Packwood Creek 300 515-1,477 150-400
The modeling results indicate the channel carrying capacity is likely less than the peak flows being discharged into them. As such, increasing peak flows from the City’s minor drainage system may exacerbate channel capacity issues downstream. This finding further supports the City’s stormwater management approach of limiting discharges from its system.

5.6 Assumptions and Limitations
The following section describes the specific assumptions and limitations regarding this section:

1. The comparison between summed outfall discharges and waterway capacity is inherently uncertain.

Outfalls are distributed in space and time, and travel time, attenuation, and channel storage can prevent the summed peak from occurring at a single cross-section. Actual performance may also be controlled by localized restrictions, culverts, maintenance condition, vegetation, sediment, tailwater, and concurrent irrigation or flood-control flows. Accordingly, the summed outfall peak is a planning-level screening metric, not a deterministic prediction of exceedance at a specific location.

The data utilized for the hydraulic capacity evaluation of the waterways is considered planning level; no field survey was conducted. Feasibility studies should be conducted prior to final design.

2. The City’s minor and major drainage systems interact highly with each other. To understand the magnitude of interaction, the Modoc Ditch was added to the USEPA-SWMM minor drainage system model. Based on the results of this addition, it is recommended that future SWMP updates incorporate all waterways into the minor drainage system model.

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3. The Future Conditions outfall flow values are based on the final Future Conditions SWMM model and represent planning-level peak discharges from the modeled storm drain system to the receiving waterways. These values are appropriate for master planning and capital improvement screening but should not be used as final design discharges without project-specific confirmation.

4. The waterway hydraulic analysis relies on City-provided 2006 LiDAR and available cross-section information developed during previous planning efforts. In some locations, ponded water or vegetation affected the LiDAR surface, and the topographic data were adjusted in those areas. No new field survey or replacement terrain model was incorporated as part of this SWMP update.

Accordingly, the results are appropriate for planning-level evaluation, and current channel and crossing survey data should be obtained before project-specific design or detailed capacity analysis.

5. Future Conditions discharge assumptions should be revisited as development occurs, as drainage areas are refined, and as final designs for FCIPs are prepared.

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 6-1
CHAPTER 6 HYDRAULIC ANALYSIS OF INTERIOR

DRAINAGE SYSTEM
This chapter summarizes the planning-level hydraulic evaluation of the City’s interior, or minor drainage system (storm drains, storage basins, and pumps) and compares modeled results to anecdotal information reported on system deficiencies. Both existing conditions and future conditions are described.

6.1 Modeling Objectives
Modeling and analysis of the City’s existing conditions and future conditions stormwater basins, pumps, and pipe network were performed. This modeling and analysis effort had three main objectives:

1. The first was to identify capacity deficiencies of the existing basins, pumps and pipe network based on existing development.

2. The second was to identify capacity deficiencies of the existing basins, pumps, and pipe network based on adding future development occurring per the General Plan that would impact the existing facilities.

3. The third was to plan for the future basins and pipe network to serve future growth areas within the City.

6.2 Current and Previous SWMP Modeling Approach

6.2.1 1994 SWMP
The 1994 master plan modeling approach differed from the present approach in that it relied on HEC-1 for hydrologic computations and a kinematic wave approach for flow routing, while capacity evaluation for portions of the conveyance system was performed using Manning’s equation methods. The kinematic wave method assumes the water surface slope is approximately equal to the conduit/plane slope and does not represent backwater and pressurization to the same degree as dynamic wave routing.

6.2.2 Current SWMP
The modeling for this SWMP was conducted using USEPA-SWMM Version 5.2.4. The USEPA-SWMM model used the dynamic wave equations, which can represent pressurized flow, flow reversal, and non-dendritic layouts. The dynamic wave equations require more computational time and smaller time steps for numerical stability than the kinematic wave equations.

The hydrologic analysis component of USEPA-SWMM was described in Section 4. The runoff from the hydrologic analysis enters the basins, pumps, and pipe network model components through the model’s hydrology layer.

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 6-2
Hydraulic routing within the basin–pump–pipe network model performed using EPA SWMM dynamic wave routing, solves the full one-dimensional Saint-Venant equations and can represent conditions relevant to urban drainage systems including surcharged/pressurized flow, backwater effects, flow reversal, and non-dendritic network layouts. This capability is particularly important in relatively flat terrain and in systems with pump stations and interconnected trunk lines where hydraulic grade line (HGL) interactions can control system performance. For this SWMP, dynamic wave routing is used because it is better suited to represent the operational and hydraulic controls present in the City’s storm drain system (including pumped discharge constraints and non-dendritic connectivity).

6.3 Existing Conditions Model Components
As described previously, the City’s minor drainage system is made of storm drainpipes, pump stations, and storage basins. The existing conditions model update utilized the 2005 stormwater model as a starting point.

The 2005 model was compared to the City’s most recently updated GIS data to find missing pipes, pumps, and storage basins as follows:
 Storm Drainpipes: The 30-inch and greater diameter storm drainpipes installed since the 2005 model were identified. As-built drawings for these pipes were acquired from the City, and the missing pipes were added to the Existing Conditions model.

Standard circular storm drain conduits were generally modeled using a Manning’s roughness coefficient of 𝑛𝑛 = 0.013, representative of RCP. Different roughness coefficients were retained where they were present in the City-provided baseline model or where model elements represented other materials like open channels, bioswales, or overland-flow pathways.  Pump Stations: A list of currently operated pumps, pump flow data, pump on and off elevations, and available rating curves were acquired from the City. The Existing Conditions model was updated with this most recent pump information.
 Storage Basins: Storage basins implemented since the 2005 model were identified. Stage-storage curves and elevation data were received from the City for these storage basins. Additionally, basins that were included in the 2005 stormwater model, but that were significantly altered since, were also identified and updated.
 Dividers: The 2005 stormwater model included dividers, which represent junctions with divided flow.

The dynamic wave equations used in the 2023 model update do not require junctions to be specifically defined as dividers to model divided flow. Therefore, new dividers were not added to the model, while the 2005 dividers were retained.

STORMWATER MASTER PLAN
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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 6-3
Table 6.1 contains a summary of 2005 stormwater model components and the current model components. Figure 6.1 shows the Existing Conditions model components.

Table 6.1 Summary of Existing Conditions Model Update
Model Component 2005 Model Updated Existing Conditions Model Subcatchments 451 subcatchments 708 subcatchments
18,698 acres 19,357 acres
Junctions and Dividers 528 junctions and dividers 740 junctions and dividers Pipes 531 conduits 804 conduits

67.7 miles 78 miles
Outfalls 83 outfalls 130 outfalls
Storage Basins 44 basins 78 basins
Pump Wet Wells Not modeled 40 wet wells
Pumps 22 pumps 51 pumps

Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
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Last Revised: August 10, 2026 [ENTER PROJECT WISE PATH NAME TO MXD] For Example:pw://Carollo/Documents/Client/CA/ClientName/10265A00/Data/GIS/Figure_01_01.aprx O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 6.1 Existing Conditions Model Components

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
Modeled Storm Drains
#* Outfall
"=) Pump Station
Modeled Storage Basin
!² Retention
!² Detention
!² Temporary
Non-Modeled Storm
Drains
City Limits
Railroads
County Parcels

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 6-5

6.3.1.1 Storage Basins
Storage basins are represented in USEPA-SWMM using storage nodes with basin-specific stage-storage curves. Basin inverts, crest elevations, and outlet structures control the routing of inflows through basin storage and into downstream conveyance or pumped discharge facilities. Stage-storage relationships were developed using City-provided basin data. Chapter 2 lists the storage basins included in the model.

6.3.1.2 Pumps
Pump stations are represented in USEPA-SWMM using pump elements with control settings (on/off elevations) and performance characteristics. Pump stations serve as critical control points that regulate discharge to receiving ditches and canals subject to entitlement and operational constraints. Chapter 2 lists the pump stations included in the model.

6.3.1.3 Pipe Network
Chapter 2 summarizes the storm drain contained in the City’s GIS data for all storm drain. The modeled pipe network includes trunk and major conveyance infrastructure used for master planning evaluations (pipes 30-inches or greater). Table 6.1 summarizes the portion of the City’s system included in this SWMP model.

6.3.1.4 Overland Flow/Ponding
The purpose of this modeling is to understand the capacity of the stormwater management infrastructure, generally defined as the pipes, pump stations, and storage basins. Overland flow areas, such as streets and other overland flow paths, are not included.

However, when the capacity of the defined system is exceeded in the model, the stormwater will surcharge the modeled system. If the areas where the stormwater can surcharge to are not defined, that stormwater will be lost from the system (it does not get stored by default to reenter the defined system).

For this SWMP model, these overland locations were defined by creating ponded areas at the model junctions. The ponded area was approximated using the street ROW area associated with the tributary subcatchment.

Where mapped ROW information was available, the corresponding ROW area was used to represent surface ponding at the receiving junction. Where no direct tributary subcatchment or other representative surface-storage area was available, a nominal ponded area of 100 square feet was generally assigned so that surcharged flow would be retained within the model and could reenter the drainage system as capacity became available. Project-specific values were retained where more representative ponding or routing information was available.

Tables summarizing the Existing Conditions model hydraulic parameters can be found in Appendix E.

STORMWATER MASTER PLAN
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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 6-6

6.4 Existing Conditions Model Results
The Existing Conditions storm event (3 2-year, 24-hour storm events spaced 6 days apart) was executed in the model. The model results were reviewed with City staff. Where the model results did not seem to match anecdotal information, the model inputs were revised. Once the modeling was complete, the results were compared to the City’s criteria described in Chapter 3.

Figure 6.2 shows the existing conditions HGL results for each junction. Figure 6.3 shows the existing conditions HGL results for each storage basin. Orange and red symbols identify locations where the modeled water level exceeds the City’s screening criteria, with red representing a longer-duration exceedance than orange.

These symbols are screening flags and do not automatically mean that flooding has been observed at the location or that a separate capital project is required. Some flagged locations represent pressure within a closed pipe, localized or short-duration ponding, simplified assumptions used to represent surface storage, or conditions associated with another system constraint.

The flagged results were reviewed considering the modeled depth and duration, the representation of surface ponding area, the physical function of the modeled node, hydraulic connectivity, available City operations and maintenance information, and whether the condition was addressed through an identified capital improvement. Appendix F lists the flagged junctions and storage nodes and documents the resulting findings.
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Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
S a i n t J o h n s R i v e r
Modoc Ditch
Packwood Creek
Mill Creek
Evans Ditch
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 6.2 Existing Conditions Maximum Junction HGL Results

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
Max HGL (Junctions)
Below ground
0-6 inches for less than
72 hours
0-6 inches for longer
than 72 hours
> 6 inches for less than
72 hours
>6 inches for longer
than 72 hours
#* Outfall
"=)
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Existing Storm Drains
Channel
Saint Johns River
Railroads
City Limits
County Parcels
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Goshen Ave
Houston Ave
Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
S a i n t J o h n s R i v e r
Modoc Ditch
Packwood Creek
Mill Creek
Evans Ditch
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 6.3 Existing Conditions Maximum Storage HGL Results

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
Maximum HGL (Storage Basins)
!² >1 ft from top of basin
!²
Between 1 ft and top of
basin
!²
Above top of basin less
than 72 hrs
!²
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longer than 72 hours
#* Outfall
"=)
Pump Station
Existing Storm Drains
Channel
Saint Johns River
Railroads
City Limits
County Parcels

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 6-9
Overall, the City’s system generally performs in a manner consistent with the City’s historical expectations, except for three priority areas identified by City operations and maintenance staff:
 Area 1: The intersection of South County Center Drive and West Walnut Avenue experiences flooding during storm events due to insufficient wet well capacity and the absence of an overflow outlet to Evans Ditch. This condition is not fully reflected in the model because the flooding mechanism is controlled by localized wet well/sump storage and the lack of an emergency overflow path, rather than a larger trunk storm drain capacity deficiency represented at the master planning model scale.  Area 2: A pipe size reduction along North McAuliff Street causes recurring debris blockages and approximately 6 inches of flooding at the intersection of Houston Avenue and McAuliff Street, a major roadway corridor. This area is not shown in the modeling results as this system is not included in the modeling; the diameter of the storm pipe is less than the minimum diameter included in the model.  Area 3: The Kiwanis Park Basin and wet well system require improvements to the hydraulic connection between the existing storage basin and downstream wet well. The improvement includes lowering or replacing the connection pipe and modifying or deepening the existing wet well so the basin can drain more effectively and better use its available storage volume.

The recommendations for these areas are described in Chapter 8.

6.5 Future Conditions Model Components
The Future Conditions model builds on the Existing Conditions model and incorporates General Plan buildout, known future development areas, revised future drainage areas, planned trunk storm drain infrastructure, future storage facilities, and the FCIPs developed as part of this SWMP. The Future Conditions model is intended to evaluate the long-term drainage infrastructure needed to serve future growth while remaining consistent with the City’s storage-first and controlled-discharge stormwater management strategy.

The future conditions model components were developed as follows:
 Storage Basins: Future storage facilities are represented in USEPA-SWMM using storage nodes with conceptual stage-storage curves consistent with planning-level facility footprints and assumed design depths. For proposed facilities, City standards specify that infiltration should not be credited in basin sizing. Therefore, infiltration/seepage is set to zero (or seepage is not allowed) in the future conditions model.

Previous planning included a combined “park-basin” concept and represented the park turf portion as a shallow storage component (including freeboard). However, updated City direction indicates the combined park-basin approach is no longer applicable. The current intent is to implement regional facilities as standalone retention basins.

Conceptual sizing for this storage basins includes order-of-magnitude geometry such as approximately 23 feet of total depth, 18 feet of water depth, and conservative freeboard allowances.  Pumps: Future pump stations are included where gravity discharge is not feasible and where discharge to receiving facilities must be regulated. Pump station representation follows the same methodology as existing conditions, with conceptual pump controls and capacities aligned with the planned basin operating range and downstream entitlement/receiving constraints.

STORMWATER MASTER PLAN
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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 6-10
 Pipe Network: Future trunk conveyance is represented as conduits sized for master plan performance under the future conditions screening storm. Pipes included in Future Conditions assume each pipe is at least 18 inches in diameter to account for maintenance/reduce future clogging. Pipe slopes are also entered with an assumed minimum slope of 0.001 feet/feet unless project-specific conditions require a different configuration. Final pipe size, slope, cover, alignment, and tie-in elevations should be confirmed during project-specific design.
 Overland Flow/Ponding: The Future Conditions model applies the same general ponding approach used for Existing Conditions. For future tributary subcatchments where mapped existing street ROW was not available, the ponded area at the receiving junction was generally estimated as 23.88 percent of the tributary subcatchment area. This percentage represents the average ROW proportion developed from a geospatial review of existing modeled subcatchments. Where mapped ROW or more representative project-specific information was available, that information was used instead.

Where no direct tributary subcatchment or other representative surface-storage area was available, a nominal ponded area of 100 square feet was generally assigned, subject to project-specific exceptions. These ponded areas are planning-level representations used to retain surcharged flow in the model and do not represent surveyed street-storage limits or detailed grading conditions.  Outfalls and Tie-ins: Future outfalls and tie-ins were modeled to represent anticipated discharge points from future development areas and proposed FCIP infrastructure. Where future improvements connect to existing infrastructure, existing elevations, downstream capacity, and receiving constraints may limit the ability to fully eliminate local surcharge or ponding. These constraints are considered part of the planning-level evaluation and should be refined during final design.

Table 6.2 contains a summary of 2005 stormwater model components and Future Conditions model components. Figure 6.4 shows the Future Conditions model components. Tables showing the Future Conditions model hydraulic parameters can be found in Appendix G.

Table 6.2 Summary of Future Conditions Model Update
Model Component 2005 Model Future Conditions Model
Subcatchments 451 subcatchments 881 subcatchments
18,698 acres 26,734 acres
Junctions and Dividers 528 junctions and dividers 929 junctions and dividers Pipes 531 conduits 1007 conduits

67.7 miles 114 miles
Outfalls 83 outfalls 126 outfalls
Storage Basins 44 basins 105 basins
Pump Wet Wells Not modeled 40 wet wells
Pumps 22 pumps 52 pumps

STORMWATER MASTER PLAN
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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 6-11

6.6 Future Conditions Model Results
The Future Conditions model was evaluated using the Future Conditions design storm described in Chapter 4. The model incorporates General Plan buildout, known future development areas, revised future drainage areas, proposed future trunk conveyance, future storage facilities, and the FCIPs developed as part of this SWMP.

Future Conditions model results were reviewed using the criteria described in Chapter 3, including modeled flooding depth and flooding duration at junctions and available freeboard or maximum storage utilization at storage facilities. The results were used to evaluate whether the proposed future storm drain network, storage facilities, pump controls, and tie-ins provide planning-level capacity for future buildout conditions.

Figure 6.5 shows the Future Conditions maximum junction HGL results. Figure 6.6 shows the Future Conditions maximum storage HGL results.

The maximum HGL is the highest modeled water level at each storm drain junction or storage during the Future Conditions design storm after the proposed FCIPs are included. Orange and red symbols identify locations where the modeled water level exceeds the City’s screening criteria, with red representing a longer-duration exceedance than orange.

These symbols do not automatically mean that flooding has been observed at the location or that a separate capital project is required. Some flagged locations represent pressure within a closed pipe, localized or short-duration ponding, simplified assumptions used to represent surface storage, constraints at an existing connection, or a condition already addressed as part of a proposed FCIP. Appendix H lists the remaining flagged junctions and documents why each location was or was not carried forward as a separate improvement.
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Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 6.4 Future Conditions Model Components

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
!² Future Storage Basin
Future Storm Drains
FCIP Tributary Area
#* Outfall
"=) Pump Station
Modeled Storage Basin
!² Retention
!² Detention
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Mill Creek
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Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 6.5 Future Conditions Maximum Junction HGL Results

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
Maximum HGL (Junctions)
Below ground
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72 hours
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than 72 hours
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72 hours
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Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
S a i n t J o h n s R i v e r
Modoc Ditch
Packwood Creek
Mill Creek
Evans Ditch
Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 6.6 Future Conditions Maximum Storage HGL Results

CITY OF VISALIA, CA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
Maximum HGL (Storage Basins)
!² >1 ft from top of basin
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basin
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than 72 hrs
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longer than 72 hours
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#* Outfall
Existing Storm Drains
Channel
Saint Johns River
Railroads
City Limits
County Parcels

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 6-15

6.7 Assumptions and Limitations
The following assumptions and limitations apply to this section:

1. The Existing Conditions screening design storm is intended to reflect the City’s contemporaneous conveyance design criteria used for the minor/collector drainage system and to avoid artificially classifying most of the legacy system as deficient. Incoming development has historically been held to a 2-year level of protection for conveyance using the Rational Method, and storage basin sizing practices have relied on Rational Method runoff coefficients.

2. Existing Conditions deficiencies were evaluated using a storm sequence consisting of three 2-year, 24-hour rainfall events spaced six days apart, which provides a total rainfall depth of approximately

4.2 inches while allowing partial soil moisture recovery consistent with SWMM drying time behavior.

This event sequence was selected because it produces effective runoff behavior that is closer to the City’s adopted Rational coefficients and is considered a reasonable representation of the design criteria used to build much of the existing conveyance system.

3. Some existing storage facilities may have overflow mechanisms that are not explicitly represented in the model; field observations and maintenance history should be used to confirm deficiency status and prioritize improvements.

4. Modeled surface ponding at junctions is based on approximate ponded areas and is intended to represent the relative magnitude of street flooding. The model does not provide detailed two-dimensional overland flow routing, curb-and-gutter spread, inlet interception, or parcel-level flooding analysis.

5. Locations exceeding the screening criteria, or identified through corroborating field observations, should be carried forward into the capital improvement planning process. This approach recognizes that moderate street flooding is expected and has historically been acknowledged in prior master planning; therefore, the deficiency definition focuses on persistent or severe conditions rather than incidental nuisance ponding.

6. The Future Conditions model represents planning-level buildout conditions based on General Plan land uses, known future development information, proposed FCIP infrastructure, and City direction available at the time of this SWMP update. Future changes in land use, development phasing, grading, or drainage standards may require future model updates.

7. The Future Conditions model does not include basin seepage or infiltration for storage sizing unless a project-specific or City-accepted basis was available. Site-specific infiltration or seepage assumptions should be supported by geotechnical information and accepted by the City before being used for final design.

8. Residual modeled flooding or high HGL locations do not automatically indicate that a proposed FCIP is ineffective. These results may reflect existing tie-in constraints, downstream receiving limitations, localized model assumptions, or the City’s accepted planning approach that moderate street ponding may occur during the design sequence.

9. The Future Conditions model is intended to support master planning, capital improvement development, and funding/nexus analysis. It is not a substitute for final drainage design, detailed grading design, site-specific hydrologic and hydraulic calculations, utility coordination, or construction-level design.

STORMWATER MASTER PLAN
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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 6-16

10. Some model instability may occur near the tail end of storm hydrographs, particularly where flow rates become very small and the modeled system includes very flat or very steep hydraulic grades.

This type of late-hydrograph oscillation is a known limitation of SWMM dynamic-wave routing and is generally associated with numerical water-balance behavior at low flows rather than peak-flooding performance. For the FCIP evaluations, isolated instability occurring after the peak runoff period was not used by itself as the basis for increasing pipe size or storage volume. Model results were instead reviewed based on peak hydraulic grade, maximum flood depth, flooding duration, and whether residual street ponding remained within the City’s revised acceptable tolerance. Where instability coincided with peak flooding or materially affected flood-depth results, the affected FCIP was reviewed and instabilities were remedied.

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AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 7-1
CHAPTER 7 STORMWATER MANAGEMENT ALTERNATIVES
Stormwater planning typically distinguishes between a minor (collector) drainage system intended to manage frequent storms with tolerable nuisance flooding and a major drainage system intended to convey larger, less frequent events (e.g., principal open channels and waterways).

A common drainage standard is to limit major damage from larger events and limit nuisance flooding from more frequent events. Within Visalia, relatively flat topography can promote distributed (rather than concentrated) runoff pathways, and the drainage system has historically been planned with an understanding that some moderate street flooding/ponding may occur during storms that exceed minor-system capacity.

A defining constraint for stormwater management in Visalia is that major conveyance pathways are largely comprised of managed creeks/ditches and irrigation facilities, many of which are elevated relative to surrounding land and subject to shared-use agreements and operational constraints. Because downstream receiving capacity is limited and stormwater discharges can coincide with irrigation deliveries and/or flood-control releases, planning alternatives must address not only local conveyance but also timing and throttling of discharges to managed waterways.

7.1 Level of Protection
Visalia’s established drainage design criteria are aligned with conveyance sizing for relatively frequent storms. For higher-intensity storms, street ponding is expected until capacity becomes available and/or ponded water migrates along defined overland flow paths. This approach intentionally limits peak discharges from the pipe network to downstream facilities and receiving waterways, which is important given the limited receiving capacity and operational constraints of downstream channels.

The City’s relatively flat topography contributes to distributed ponding and localized nuisance flooding, rather than rapidly concentrated, high-velocity flooding. As a result, the controlling considerations at most locations are the extent and duration of street ponding, the protection of structures and critical access routes, and the ability to convey or store runoff without creating downstream impacts. Based on historical and current design practice, much of the City’s underground storm drain network is generally consistent with approximately a 2-year level of protection for the minor conveyance system. Higher levels of protection may be present in select corridors where facilities were constructed as trunklines or as part of specific capital projects.

Increasing the level of protection (for example, widespread upsizing of storm drainpipes to convey substantially larger events) can reduce localized street ponding in some locations; however, it can also shift flood risk downstream, increase peak discharge rates to channels and ditches with limited capacity, and require substantial reconstruction of the existing system. Prior master planning efforts recognized that materially increasing the systemwide level of protection has historically been considered cost prohibitive, and that system performance is often governed by downstream receiving limitations and operational controls, not pipe capacity alone.

City staff report the current system performance is meeting their expectations. They do see some nuisance flooding, but, in general, very few areas are in need of improvement.

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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 7-2
Given this information, the following is the recommended level-of-protection framework:

1. Maintain minor-system planning consistent with the City’s established conveyance design intent, recognizing that street ponding during more intense storms is an expected outcome and must be safely managed via overland pathways.

2. Prioritize targeted conveyance improvements where they provide clear benefit (e.g., critical access routes and repetitive localized flooding locations), while avoiding widespread upsizing that would outpace downstream discharge constraints.

3. Emphasize improvements that increase system resiliency through storage, discharge throttling, and operational coordination with managed waterways, rather than relying solely on pipe conveyance expansion.

7.2 Stormwater Storage
When downstream drains have limited capacity and improvements are not practical due to either limited right of way, aesthetics, protecting riparian habitat, or capital costs, then stormwater storage is the most practical measure for managing runoff. Major advantages of storage include infiltration to recharge groundwater supplies, downstream conveyance systems can have less capacity, water quality can be improved, and sediment can be controlled. Disadvantages include land availability and acquisition, ongoing operation and maintenance of pumping facilities, potential unsightliness, and unreliability if not located correctly.

If storage basins are not located to capture runoff naturally, collection systems must capture and convey runoff to the basins. When storms larger than the design event occur, or if inlets are blocked due to lack of maintenance, runoff will follow the natural gradient and could bypass the planned storage facility.

Storage basins can be classified as either retention or detention basins. Retention basins have no outlet and rely on evaporation and infiltration to drain the basin. Detention basins can be drained by gravity pipes, pumps, infiltration, evaporation, or a combination of these methods. For in-town basins, the maximum detention time, based on aesthetics and mosquito control, is five days, while the City prefers to have detention basins drained in two days. For basins outside of town, draining all water within a specific time is not a requirement.

Visalia’s stormwater system has long relied on storage in combination with managed waterways and pumping to accommodate the limited downstream receiving capacity and the operational constraints imposed by shared-use channels/ditches. The planning emphasis has evolved toward aligning storage performance with the City’s conveyance design intent and downstream discharge limitations using long-duration rainfall representations that reflect how runoff volume accumulates over multi-day conditions.

The following discusses alternative storage approaches and implications:

1. Detention vs. retention: Retention can reduce reliance on downstream discharge capacity but may be land-intensive and sensitive to soil/percolation conditions and groundwater considerations.

Detention can be effective where controlled releases and pumping can be coordinated with available receiving capacity, but it requires operational reliability and maintenance of control facilities.

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 7-3

2. Shared-use vs. single-use facilities: Shared-use facilities (e.g., park-basin configurations) can improve land-use efficiency, but require explicit consideration of public safety, water depths, and drawdown timing.

3. Crediting infiltration in sizing: For detention basin sizing, City standards indicate that infiltration should not be incorporated into detention basin sizing; detention basin seepage should be set to “not allowed” (or equivalent). Retention basins may still rely on infiltration/evaporation as the drainage mechanism, but performance assumptions should be consistent with field observations and accepted criteria. It should be noted that infiltration and evaporation were not included in the modeling conducted for this study, except where current in-situ infiltration information was available. This credit discussion applies to future design projects.

The City recently transitioned to stand-alone retention basins. Observations from this change (both positive and negative) should be noted over time. City staff should reconvene after a reasonable amount of time and discuss the observations to understand if this approach is the best for the City.

7.3 Temporary Storage Basins
The City’s long-term stormwater management strategy is to convey runoff to regional standalone retention basins that serve as primary control points for peak flow attenuation and stormwater management. However, until regional basins are constructed, expanded, or otherwise available (and in areas where regional capacity is constrained), new development should provide interim on-site storage to mitigate increases in downstream peak flows and runoff volumes attributable to development. These temporary facilities are intended to function as near-term controls that can be modified, integrated, or phased out as regional infrastructure becomes available.

Temporary storage facilities shall be designed so they do not conflict with the ultimate drainage pattern identified in this SWMP. Where future regional trunk lines or basins are planned, temporary facilities shall be configured to allow future connection, modification, or removal as permanent infrastructure is implemented. Final requirements for temporary storage shall be coordinated with City development review and shall remain consistent with the drainage criteria described in Chapter 10.

7.4 Stormwater Conveyance
Future storm drain trunk lines will be required to convey runoff generated from newly developed areas.

The future trunk lines should be installed as part of the street projects to the extent practicable as the future areas of the City are developed.

Stormwater conveyance methods in Visalia include combinations of:

1. Underground storm drainpipe networks (minor system).

2. Open channels and managed waterways/ditches (major system).

3. Overland flow pathways that convey stormwater when the underground network surcharges.

Open channel conveyance systems are the least expensive method of managing stormwater runoff when the right of way is available, riparian habitat is managed, and aesthetics can be maintained.

Future projects considered in this SWMP generally focus on installing storm drainpipe to convey runoff to storage basins. Open channels may also be feasible in some locations where ROW, maintenance, habitat,

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 7-4
safety, and regulatory considerations can be addressed. Future conveyance improvements identified in this SWMP are intended to route runoff from planned development areas to future storage facilities, existing receiving facilities, or controlled discharge points. The purpose of future trunk conveyance is not to maximize discharge to downstream waterways, but to provide a planned drainage backbone that works in combination with storage and controlled release.

Where upsizing of existing or planned conveyance is needed to serve development beyond the limits of a specific project, the improvement should be evaluated using the master plan implementation criteria described in Chapter 10. This is particularly important for oversized lines or deeper trunk infrastructure that may serve multiple future development areas and may require reimbursement or cost-sharing considerations.

A key implication for conveyance planning is that enlarging local conveyance capacity without addressing downstream constraints can shift flooding impacts rather than resolving them. Because stormwater discharges are often constrained by downstream ditch/creek capacity and operational conditions, the conveyance system must be planned as part of an integrated storage + controlled discharge + overland relief framework.

7.5 Entitlement Flow Management Alternatives
Stormwater runoff has historically discharged into natural creeks and ditches that flow through the City.

Many of these same conveyance systems are also used to convey irrigation deliveries and flood control releases from Kaweah Lake.

If irrigation deliveries and/or flood control releases occur at the same time as an intense storm on the town, the rate at which City runoff can be discharged into the channels may be limited, particularly to the privately owned channels.

To avoid this conflict, the City is considering methods to temporarily manage the irrigation flows and flood control releases. This will provide additional capacity for the management of stormwater runoff in the City.

The maximum entitled irrigation and flood flows are controlled by the Kaweah and St. John’s Rivers Agreement. The entitlement and one day storage for each of the creeks and ditches passing through Visalia are summarized in Table 7.1.

Table 7.1 Entitlement Flows and Volumes
Source Channel Maximum Winter Entitlement (cfs) One Day Storage (ac-ft) Lower Kaweah River Packwood Creek 265 526
Evans Ditch 54 107
Mill Creek 99 196
Sub-Total 418 829
St. John’s River Modoc 99 196
Total 517 1,025
All or any portion of the entitled irrigation flows for a one-day period could be temporarily stored upstream of Visalia to provide additional conveyance capacity in downstream channels for stormwater runoff. After the storm, the stored water would be released back to the channels.

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AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 7-5
It must be emphasized that any modification to management of the entitlement flows will require agreements with the irrigation companies. Possible entitlement flow management alternatives include upstream storage and flow diversion.

7.6 Assumptions and Limitations
The FCIPs developed in this SWMP do not assume that entitlement flow management alternatives will be implemented unless specifically documented for a project. Any change to irrigation, flood-control, or shared-use waterway operations would require additional coordination with the applicable ditch companies, irrigation districts, and other responsible agencies. Therefore, entitlement flow management should be considered a potential future study or operational coordination measure rather than a substitute for the storage and conveyance improvements identified in this SWMP.

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 8-1
CHAPTER 8 PROPOSED IMPROVEMENTS
CIPs were identified. The existing conditions CIPs were identified for the existing development and storm drain system to address current flooding and deficiency issues. The FCIPs were identified for the future buildout condition of the City, utilizing the General Plan future land uses, and will be implemented as areas are developed.

8.1 Capital Improvement Project Cost Estimates
The unit costs for the planning level cost estimates are based on actual costs of similar projects and line items, vendor quotes, and recent bid items available in public databases for similar projects and line items.

The unit costs were reviewed and adjusted by City staff based on current projects and City policies.

The planning level estimates include the cost of excavation, labor, materials, landscaping, restoration of existing road surface conditions, disposal of removed systems, protection of existing systems, and land acquisition, as appropriate.

The costs do not account for inflation or interest rates for a future implementation date. The cost of permits, unless identified, is not included in the estimates.

Table 8.1 shows the assumptions made for items such as engineering, construction management, project administration, etc. Table 8.2 shows the unit cost values for the project components.

Table 8.1 Associated Project Cost Assumptions
Description Unit Cost ($)
Mobilization Rate 10.0%
Contingency 30.0%
Engineering 10.0%
Construction Management 10.0%
Project Administration 7.5%
Construction Baseline Schedule and Updates $1,100
Temporary Erosion Control/ Stormwater Pollution Prevention Plan $2,800 Pothole Utilities $5,000
Construction Survey $12,000
Traffic Control $8,000

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 8-2
Table 8.2 Cost Values for Project Components
Cost Category Cost Item Unit Unit Cost ($)
RCP pipe Construct 18-inch RCP Storm Drain lf $284
RCP pipe Construct 24-inch RCP Storm Drain lf $300
RCP pipe Construct 30-inch RCP Storm Drain lf $340
RCP pipe Construct 36-inch RCP Storm Drain lf $370
RCP pipe Construct 42-inch RCP Storm Drain lf $410
RCP pipe Construct 48-inch RCP Storm Drain lf $560
RCP pipe Construct 54-inch RCP Storm Drain lf $670
RCP pipe Construct 60-inch RCP Storm Drain lf $840
General Land Acquisition(2) acre $150,000
General Perimeter Fencing(2) lf $56
General Perimeter Landscaping(2) sf $6
General ROW/Frontage (Parkway, sidewalk, curb/gutter, pavement frontage)(2)
lf $232
General ROW/Frontage (Drive Approach)(2) each $7,000
General ROW/Frontage (Corner Improvements)(2) each $14,000 Structure Construct Storm Drain Manhole / Junction Structure each $16,000 Structure Construct Basin Inlet / Outlet Structure each $32,000 Structure Tie-In to Existing Storm Drain / Existing Utility each $10,900 Storage basin Storage Basin Excavation / Regrading(1) y3 $33 Storage basin Basin Site Restoration / Irrigation Repair Allowance LS $54,500 Storage basin Basin Access / Miscellaneous Appurtenances LS $27,300 Pump / wet well Small Stormwater Pump Installation Allowance each $272,300 Pump / wet well Pump Wet Well Modification / Replacement Allowance LS $199,100 Pump / wet well Small Force Main / Pump Discharge Pipe lf $164 Open Channel / Swale Construct Trapezoidal Drainage Swale / Channel* y3 $33 Notes:
lf - linear foot; y3 - cubic yard; sf - square foot; LS - lump sum. (1) Planning-level unit cost of $33 per y3 was used for storage basin excavation and regrading, consistent with City direction.

Actual earthwork costs may be higher or lower depending on site conditions, excavation and grading requirements, material suitability, hauling and disposal needs, and whether excavated material can be beneficially reused or removed by others in exchange for the material.
(2) Where applicable, proposed basin footprints were represented as equivalent-area 2:1 rectangles. Perimeter fencing was assumed to be approximately 15 feet outside the top-of-basin footprint, and an additional 15-foot-wide landscape buffer was assumed outside the fence. The land-acquisition area includes the basin footprint and these perimeter allowances. Frontage improvements were assumed along one long side and one short side of the conceptual site, with a 5-foot allowance at each end. One drive approach and one corner-improvement allowance were included per proposed basin. Where project-specific ownership, existing-site conditions, frontage configuration, and other information was available, the quantities were adjusted accordingly.

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 8-3

8.2 Existing Conditions - Capital Improvement Projects
Three Existing Conditions CIPs were identified. Project types include pipe removal and replacement, pump wet well replacements and new pipe construction.

The Existing Conditions CIPs are summarized in Table 8.3. Detailed project descriptions, figures, quantities, and cost estimates are provided in the CIP cut sheets in Appendix I. Figure 8.1 shows the locations of the Existing Conditions CIPs.

Table 8.3 Existing Conditions CIPs Brief Descriptions and Costs Existing Conditions Description Total Project Cost
CIP No. 1 South County Center Drive Wet Well & Evans Ditch Overflow Upgrade $424,700 CIP No. 2 North McAuliff Street Storm Drain Replacement between Houston & Douglas $512,700 CIP No. 3 Kiwanis Park Basin and Wet Well Improvements $450,300 Total Cost: 1,387,700

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Ave 320
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Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
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Existing CIP#2
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Last Revised: August 10, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 8.1 Existing Conditions Capital Improvement Projects Locations

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
!²
Deepen Existing Pump
Wet Well
"=)
Replace Existing Pump
Sump
Existing CIP
"=) Pump Station
Modeled Storage Basin
!² Retention
!² Detention
!² Temporary
Existing Storm Drains
Channel
Saint Johns River
Railroads
City Limits
County Parcels
"=)

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 8-5

8.3 Future Conditions - Capital Improvement Projects
FCIPs were developed to provide the planned drainage infrastructure needed to serve General Plan buildout and known future development areas. The proposed improvements include new trunk storm drain, storm drain upsizing or replacement, future standalone retention basins, storage basin expansion or modification, basin inlet/outlet structures, tie-ins to existing or planned infrastructure, and pump or wet well-related improvements where required by the modeled drainage configuration.

The FCIPs were developed using the Future Conditions model with proposed FCIPs as described in Chapter 6.

The projects are intended to provide a planning-level drainage backbone for future growth while maintaining the City’s storage-first and controlled-discharge stormwater management strategy. Because the City’s receiving waterways have limited and operationally constrained capacity, the future improvements emphasize storage, controlled routing, and targeted conveyance rather than unrestricted downstream discharge.

The FCIPs are summarized in Table 8.4. Detailed project descriptions, figures, quantities, and cost estimates are provided in the CIP cut sheets in Appendix J. Figure 8.2 shows the locations of the FCIPs and their tributary areas.

Table 8.4 Future Conditions CIPs Brief Descriptions and Costs Future Conditions
CIP(1) Urban Growth Tier Description Total Project Cost FCIP No. 0 Tier 3 Carlton Acres Storm Drain and Basin Improvements $30,796,300 FCIP No. 1N Tier 3 Avenue 320 and Linwood Street Storm Drain and Basin Improvements $14,872,800
FCIP No. 1S Tier 1 Modoc Basin Storage Improvements $48,322,600 FCIP No. 2E Tier 2 North Giddings Street Storm Drain Improvements $626,800 FCIP No. 2W Tier 3 Mooney Boulevard and Riverway Drive Storm Drain Improvements $1,201,300
FCIP No. 3 Tier 1 Foxwood Park Basin Storage Improvements $4,565,600 FCIP No. 4 Tier 1 River Run Ranch Basin West Pump Improvements $569,200 FCIP No. 5 Tier 3 River Run Ranch East Storm Drain and Basin Improvements $3,688,500
FCIP No. 6 Tier 2 Scenic Corridor Northwest Storm Drain and Basin Improvements $11,071,900
FCIP No. 7 Tier 1 Hillsdale Basin and Shirk Road Storm Drain Improvements $4,352,700
FCIP No. 8 Tier 1 Goshen Avenue and Goshen/Virmargo Basin Storm Drain Improvements $13,410,600
FCIP No. 9 Tier 2 Southwest SR-198/Shirk Road Drainage Area Storage Basin Improvements $8,065,000
FCIP No. 10 Tier 2 Scenic Corridor Southeast Storm Drain and Basin Improvements $4,937,000
FCIP No. 11 Tier 3 Walnut Avenue and Road 86 Storm Drain and Basin Improvements $11,161,700
FCIP No. 12 Tier 2 Shirk Road and Tulare Avenue Storm Drain and Basin Improvements $9,531,300

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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 8-6
Future Conditions
CIP(1) Urban Growth Tier Description Total Project Cost FCIP No. 13 Tier 3 Road 152 and Houston Avenue Storm Drain and Basin Improvements $5,499,200
FCIP No. 14 Urban Reserve Area Caldwell Avenue and Shirk Street Storm Drain and Basin Improvements $20,237,100
FCIP No. 15 Urban Reserve Area South Shirk Road and Avenue 276 Storm Drain and Basin Improvements $7,180,600
FCIP No. 16E Tier 3 Avenue 272 East Storm Drain Improvements $13,347,300 FCIP No. 16N Urban Reserve Area /
Tier 3 / Tier 2 / Tier 1
Southeast Caldwell/Shirk Tributary Storm Drain and
Basin Improvements $7,081,200
FCIP No. 16W Tier 3 Avenue 272 West Storm Drain and Tagus Basin Improvements $16,029,200
FCIP No. 17 Tier 3 Demaree Road and Avenue 272 Storm Drain and Basin Improvements $17,475,300
FCIP No. 19 Tier 3 Avenue 274 and Stonebrook Area Storm Drain and Basin Improvements $8,334,200
FCIP No. 20 Tier 3 Avenue 272 and Stonebrook Area Storm Drain and Basin Improvements $3,421,700
FCIP No. 21 Tier 1 Burke Street North Basin Expansion Improvements $3,681,100 FCIP No. 22NE Tier 1 Cameron Creek Northeast Storm Drain and Retention Basin Improvements $5,087,200
FCIP No. 22NW Tier 2 Cameron Creek Northwest Retention Basin Improvements $3,036,400
FCIP No. 22S Tier 3 Cameron Creek South Storm Drain and Storage Basin Improvements $10,033,600
FCIP No. 23 Tier 3 Pinkham Street and Avenue 272 Storm Drain and Basin Improvements $13,240,900
FCIP No. 24 Tier 1 Cameron Creek North/Future Southeast Growth Area Storm Drain and Basin Improvements $7,738,400
FCIP No. 25E Tier 3 Cameron Creek South East Storm Drain and Basin Improvements $9,666,400
FCIP No. 25W Tier 2 Cameron Creek Southwest Storage Basin Improvements $5,703,600
FCIP No. 26 Tier 3 Lovers Lane South of Avenue 280 Storm Drain and Basin Improvements $10,897,200
FCIP No. 27 Tier 3 McAuliff Street and Visalia Parkway Storm Drain and Basin Improvements $14,526,300
FCIP No. 28 Tier 1 / Tier 3 / Tier 2 /
Outside UGB
South Mooney Boulevard and Avenue 264 Storm Drain
and Basin Improvements $10,778,600
Total Cost $360,168,800
Notes:
(1) FCIP numbering is not the order of priority. It is an arbitrary numbering system that is meant for identification only. !²
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Rd 68
Tulare Ave
Ave 264
Ave 272
Ave 320
W Riggin Ave
Caldwell Ave
Akers St
Plaza Dr
Demaree St
Mooney Blvd
Santa Fe St
Lovers Ln
Shirk St
Rd 148
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CIP#22NE
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Future CIP#5
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Packwood Creek
Mill Creek
Evans Ditch
Last Revised: August 11, 2026 pw:\\IO-PW-INT.Carollo.local:Carollo\Documents\Client\CA\Visalia\11246A00\Data\Storm Drain System\ O
0 4,0002,000
Feet
Disclaimer: Features shown in this
figure are for planning purposes and
represent approximate locations.

Engineering and/or survey accuracy
is not implied.

Data Sources: SSURGO, City of Visalia,
ESRI

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Figure 8.2 Future Conditions Capital Improvement Projects Locations

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY
Legend
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Modified/Proposed
Basin
Pipeline Future CIP
"=) Pump Station
Modeled Storage Basin
!² Retention
!² Detention
!² Temporary
Existing Storm Drains
Channel
Saint Johns River
Railroads
City Limits
County Parcels
FCIP Tributary Area
Public Urban Development
Growth Tiers
Urban Development
Boundary Tier 1
Urban Development
Boundary Tier 2
Urban Growth Boundary
Tier 3

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MASTER PLANS AND FINANCIAL NEXUS STUDY 8-8

8.4 Assumptions and Limitations

1. The FCIPs are intended to be implemented as future development occurs and as supporting downstream or regional drainage infrastructure is needed.

2. A priority matrix was not developed for the FCIPs because implementation timing will largely depend on development phasing, land availability, ROW needs, utility conflicts, funding availability, and coordination with roadway or development projects. Future CIP sequencing should remain flexible.

Some improvements may need to be constructed earlier than others if they are required to serve an active development area, provide downstream connectivity, or support a larger regional drainage improvement.

3. As development proceeds, the City should review the Future Conditions model, completed infrastructure, and current development plans to confirm which improvements are needed and whether project limits, pipe sizes, basin geometry, or costs should be refined before final design.

4. Future storage basin geometry is conceptual and intended for master planning, cost estimating, and impact fee/nexus study development. Final basin footprints, excavation depths, side slopes, freeboard, maintenance access, landscaping, and inlet/outlet configurations should be confirmed during project-specific design.

5. Future conveyance alignments, pipe sizes, slopes, and tie-in elevations are planning-level. Final design should confirm pipe hydraulics, available cover, utility conflicts, constructability, receiving conditions, and downstream capacity.

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MASTER PLANS AND FINANCIAL NEXUS STUDY 9-1
CHAPTER 9 WATER QUALITY MEASURES
Development of urban areas can cause adverse impacts to the natural drainage systems and receiving waters. Steps can be taken to reduce potential water quality impacts from stormwater discharges including:
 Pollutant loading from impervious surfaces can be minimized through the implementation of Best Management Practices (BMPs) and LID.
 Development projects causing erosion impacts on natural drainage systems can implement hydromodification controls to mimic natural conditions.

Under Policy P-61 of the City’s General Plan, stormwater quality and management are addressed under a scope of work separate from this SWMP. However, this section provides some general background and information about stormwater management as it relates to SWMP. Maintaining an inventory of stormwater system structures and outfalls as part of the SWMP is a pivotal component of the City’s stormwater management program. The regular inspection and maintenance of the stormwater system components in the inventory ensure that the structures are clean, serviceable, and operating properly.

9.1 Background
The 1972 amendments to the federal Clean Water Act (CWA) prohibited the discharge of pollutants from point sources to the waters of the United States unless a permit issued under the NPDES permitting program authorized the discharge. The 1987 amendments to the CWA added Section 402(p), which defined certain stormwater discharges as point sources. The amendments directed USEPA to adopt regulations establishing permitting requirements for municipal and industrial stormwater discharges. The amendments also required stormwater discharges from MS4s to obtain coverage under an NPDES permit if the system served a population greater than 100,000 based on the 1990 Census. This became known as Phase I of the stormwater program. The Phase II program later expanded permitting requirements to smaller MS4s, including communities that were below the 100,000-population threshold at the time but may have grown since.

In December 1999, the USEPA promulgated the Storm Water Phase II Final Rule, which was intended to further protect the Nation’s water resources from polluted stormwater runoff. The Phase II program expands the Phase I program by requiring operators of small MS4s (less than 100,000 residents) and operators of small construction sites to implement programs and practices to control polluted stormwater runoff, through the use of NPDES permits. In California, the federal NPDES permitting program is implemented by the State Water Resources Control Board and the Regional Water Quality Control Boards through the Porter-Cologne Act, a part of the California Water Code.

USEPA requirements fall into two primary categories: source identification and source control measures.

The source identification component requires the inventory of storm sewer systems, the identification of regulated outfalls, the mapping of watersheds, and the identification of basin characteristics tributary to the outfalls. These items are discussed in this SWMP.

The source control measures deal primarily with management practices and are intended to reduce the introduction of pollutants to stormwater runoff by identifying problem sources and illicit connections and

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CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY 9-2
establishing BMPs to control the introduction of contaminants such as suspended solids, oils, and grease.

These items are discussed in much more detail in the separate stormwater management program and are described briefly in this document.

As a federally designated Phase II MS4, the City is required to obtain coverage under an NPDES stormwater permit. As part of the permit application, the City must develop a stormwater management program that addresses six MCMs. The MCMs include:

1. Public education and outreach.

2. Public involvement and participation.

3. Illicit discharge detection and elimination.

4. Construction site stormwater runoff control.

5. Post-construction stormwater management.

6. Pollution prevention and good housekeeping.

9.2 Stormwater Management Program
In November 2005, the City developed a Stormwater Management Program to support MS4 compliance.

The Stormwater Management Program is currently being updated and will be issued as a separate document from this SWMP. The Stormwater Management Program addresses the City’s MCMs and establishes criteria and guidance for post-construction stormwater controls, including LID retention, infiltration, and treatment measures.

These requirements are primarily intended to protect and improve water quality and mitigate potential water quality impacts associated with stormwater discharges. Water quality considerations are summarized briefly in this SWMP for context, with detailed requirements and implementation guidance provided in the separate Stormwater Management Program.

This SWMP is primarily a system planning document focused on storm drainage conveyance and storage performance and the identification and prioritization of capital improvements to reduce flooding and improve system reliability. MS4 compliance, by contrast, is achieved through a combination of programmatic requirements (e.g., MCM implementation), development-facing standards, and project-level design criteria addressing water quality, flow control, and hydromodification. Although the two documents serve different purposes, they are interrelated because post-construction requirements can influence runoff volumes, timing, and peak discharge characteristics that affect storm drain system performance and the assumptions used in master planning.

For example, MS4 post-construction provisions may include hydromodification management, such as limiting developed-condition peak runoff to pre-development peak runoff for a 2-year, 24-hour design storm (or other adopted criteria). As LID implementation increases (e.g., distributed retention, infiltration, and treatment controls), modeled runoff volumes and/or peak rates may be reduced or shifted in some areas, while also introducing long-term performance and maintenance considerations that can affect realized benefits. These interactions are recognized in this SWMP to support consistency between City development requirements and the planning assumptions used to evaluate and prioritize conveyance and storage improvements.

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MASTER PLANS AND FINANCIAL NEXUS STUDY 9-3
This SWMP acknowledges that MS4 compliance may drive additional capital or programmatic needs beyond flood-capacity deficiencies, such as regional or distributed water quality improvements, flow-control measures, or expanded inspection and maintenance programs. Specific MS4 compliance projects are not defined in this SWMP unless they are also needed for drainage system performance.

Future MS4-related capital needs should be identified through the City’s Stormwater Management Program, development review process, or subsequent focused studies.

9.3 Water Quality Considerations
Runoff from the City is generated from two principal land use types: urban areas and non-urbanized agricultural areas. The relative quantity of runoff from these areas is different due to the higher level of imperviousness associated with the urbanized areas. The water quality concerns from each land use differ.

The presence of homes, offices, and businesses in urbanized areas result in substantially more human activity such as vehicular traffic. Non-point source stormwater runoff from urbanized areas generally contains higher levels of greases, oil, and heavy metals. These particles are generally deposited on streets and driveways and are washed into the storm drain collection system during rainstorms and carried downstream. Nutrients from animal waste and lawn fertilizers are also common in urbanized areas and are often introduced into the storm drainage system. Other common urban area pollutants are household waste products. In many cases household cleaning agents, pesticides and other contaminants are disposed by homeowners into the storm drainage system.

In non-urbanized agricultural areas, the types and sources of pollutants are generally more easily identified. The most common pollutants are sediments from unprotected agricultural activities. Rainfall and the subsequent runoff from agricultural fields can provide a mechanism to transport large amounts of sediment to streams. Nutrients are frequently found in non-urbanized agricultural runoff from the byproduct of agricultural fertilization and can be transported along with sediments to streams.

Unless discharging to a retention pond, the gravity storm drains are discharged directly into the major drains without treatment. The pumped discharges provide opportunities to improve water quality. The holding ponds and forebays at the pumping stations provide an opportunity to settle suspended solids, some nutrients, and some metals from urban area runoff. There may also be an opportunity to provide oil and grease separators at the pump stations.

Once in the major drains, most flows are conveyed through open channels to the west side of the City.

These channels are generally earthen or grass-lined and provide some benefit to water quality as a result of plant nutrient uptake. Velocities in these channels are generally lower than those of the collection system, which may result in settlement of some suspended solids. However, erosion from high velocities in the channels can be an additional source of suspended solids. Channel improvements should be designed to minimize the probability of erosion.

The collection and major drainage systems ultimately discharge into large ponding areas on the west side of town. These ponding areas provide significant storage and are emptied through evaporation and infiltration. Waterborne pollutants are transported to these ponding sites where the dissolved pollutants are potentially infiltrated into the subsurface and particulate pollutants are settled out.

The facilities proposed in this SWMP will not adversely impact stormwater quality. The use of detention basins and open channels may result in some improvement to water quality, through settling suspended solids and providing vegetation for nutrient uptake.

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MASTER PLANS AND FINANCIAL NEXUS STUDY 9-4

9.4 Assumptions and Limitations

1. FCIPs identified in this SWMP are intended primarily to provide drainage conveyance, storage, and controlled discharge capacity for future growth areas. These improvements are not expected to adversely affect stormwater quality. Future storage basins may provide incidental water quality benefits through sedimentation, vegetation uptake, and reduced peak discharge rates; however, these benefits are secondary to the hydraulic storage and conveyance functions evaluated in this SWMP.

2. Water quality treatment requirements for new development and redevelopment should continue to be addressed through the City’s MS4 permit requirements, LID standards, and project-specific development review. Final design of future storm drain and basin improvements should incorporate applicable water quality, erosion control, and maintenance requirements where required by City standards or regulatory permits.

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MASTER PLANS AND FINANCIAL NEXUS STUDY 10-1
CHAPTER 10 DESIGN CRITERIA FOR MASTER PLAN

IMPLEMENTATION
This chapter provides planning-level design criteria and implementation guidance for applying the SWMP to future development and City capital improvements. The criteria are intended to help the City, developers, and design engineers determine how future drainage infrastructure should be sized, coordinated, and implemented as development occurs.

The criteria in this chapter are not intended to replace the City’s adopted Storm Drainage Design Criteria, the City’s development review process, or project-specific engineering design. Rather, they provide master plan implementation guidance so that individual development projects and City capital projects remain consistent with the long-term drainage system identified in this SWMP.

10.1 Use of Stormwater Master Plan
The Future Conditions model and FCIPs identify the planned drainage backbone needed to support General Plan buildout. The master plan should be used to determine anticipated tributary areas, planned trunk storm drain alignments, future storage basin locations, estimated basin capacities, and locations where future development may need to construct or contribute toward regional drainage infrastructure.

Development projects should use this SWMP as the starting point for drainage planning. Project-specific drainage studies should confirm the applicable tributary area, downstream connection point, storm drain sizing, storage requirement, and consistency with the planned Future Conditions drainage system. Where a proposed development changes drainage patterns, modifies the assumed tributary area, or proposes a different outlet than shown in the SWMP, the applicant should demonstrate that the proposed configuration does not reduce downstream capacity, conflict with planned regional improvements, or increase flooding elsewhere.

10.2 Design Storm and Level of Protection
Future drainage infrastructure should be planned consistent with the design criteria described in Chapter 3 and the hydrologic approach described in Chapter 4. For master planning purposes, Future Conditions improvements were evaluated using a sequence of three 2-year, 24-hour storm events separated by 2-day gaps. This storm sequence provides the planning basis for the FCIPs and is intended to represent the City’s future storage and trunk drainage planning framework.

The City’s minor drainage system is intended to manage frequent storm events while recognizing that moderate street ponding may occur during larger or more intense events. Future improvements should therefore be designed to safely route runoff to storage facilities, trunk storm drains, or controlled discharge points without creating adverse downstream impacts.

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MASTER PLANS AND FINANCIAL NEXUS STUDY 10-2

10.3 Accepted Calculation Methods
Drainage calculations prepared for future development should remain consistent with the City’s adopted Storm Drainage Design Criteria and development review requirements. The Rational Method may continue to be used for site-level and local conveyance design where appropriate under City criteria.

For larger tributary areas, regional storage facilities, trunk storm drains, pump-controlled systems, or improvements that interact with the City’s master planned drainage network, hydrologic and hydraulic modeling may be required. USEPA-SWMM or another City-accepted modeling platform should be used where routed hydrographs, storage, pump controls, backwater, surcharge, or system interactions materially affect the design.

Minimum pipe size, slope, velocity, runoff coefficient, and storage calculation requirements should remain consistent with the City’s adopted Storm Drainage Design Criteria unless a project-specific drainage study demonstrates that an alternate approach is appropriate and is accepted by the City. Where the SWMP identifies larger regional infrastructure needs, the SWMP model, FCIPs, and supporting cut sheets should be used to confirm whether development-specific improvements must be sized beyond the local project drainage requirement.

Project-specific studies should document rainfall assumptions, runoff coefficients or CNs, tributary area delineations, time of concentration assumptions, storage calculations, outlet controls, downstream tie-in elevations, and any deviations from the master plan assumptions.

10.4 Tributary Area and Drainage Boundary Confirmation
The tributary areas shown in the Future Conditions model are planning-level drainage areas developed to represent General Plan buildout and proposed FCIP infrastructure. These tributary areas should be used for planning, funding, and consistency review, but they should be confirmed during project-specific design.

Final drainage boundaries should be based on detailed grading plans, survey information, roadway profiles, proposed storm drain alignments, and the planned outlet location. If final grading changes the tributary area to a planned trunk storm drain or storage basin, the project-specific drainage study should confirm that the receiving infrastructure has adequate capacity or identify the required improvement.

10.5 Future Storm Drain Design
Future trunk storm drains should generally follow the alignments, sizes, and outlet locations identified in the FCIPs unless a project-specific drainage study demonstrates that an alternate configuration provides equivalent or better performance and is accepted by the City.

For master planning, future storm drain conduits were generally modeled with a minimum diameter of 18-inches and a minimum slope of 0.001 feet per foot unless project-specific conditions required a different configuration. Final design should confirm pipe size, slope, hydraulic capacity, cover, utility conflicts, constructability, and downstream tie-in conditions.

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The City’s current maximum allowable spacing between storm drain manholes is 500 feet. For planning-level quantity and cost estimating in the FCIP cut sheets, manhole quantities were estimated using a preferred spacing of approximately 400 feet, with additional structures included where warranted by changes in pipe size, alignment, connections, or other project-specific conditions.

The 400-foot planning assumption was not incorporated as a maximum spacing requirement in the hydraulic models and does not revise the City’s 500-foot maximum for final design. Final manhole locations and spacing shall be established during project-specific design in accordance with applicable City standards.

Where a proposed development is required to construct a segment of master planned trunk storm drain, the constructed facility shall be sized to serve the ultimate tributary area identified in the SWMP, not only the project’s immediate development footprint, unless otherwise approved by the City.

10.6 Future Storage Basin Design
Future storage basins should generally be planned as standalone retention basins unless a different project-specific configuration is accepted by the City. Future storage facilities should be sized to provide the storage capacity needed for the tributary area and applicable design storm criteria.

For master planning purposes, standalone basin concepts generally assume an excavated basin configuration with approximately 23 feet of total depth, approximately 18 feet of design water depth, and freeboard allowance. These dimensions are planning-level assumptions only. Final basin design should confirm basin footprint, side slopes, maintenance access, inlet and outlet configuration, freeboard, fencing or safety requirements, landscaping, groundwater conditions, geotechnical constraints, and long-term maintenance needs.

Future storage basin sizing should generally not rely on seepage or infiltration credit.

10.7 Pump Stations, Wet Wells, and Controlled Discharge Pump stations and wet wells should be evaluated where gravity discharge is not feasible or where controlled discharge is needed because of downstream receiving constraints. Pump sizing, wet well volume, controls, and discharge location should be coordinated with the receiving system and applicable operational constraints.

Where discharge is routed to a shared-use waterway, ditch, canal, or existing storm drain system, the project-specific design should confirm that the discharge rate, timing, and outlet configuration are consistent with City requirements, receiving-system capacity, and applicable agreements or agency coordination requirements.

10.8 Pipe Oversizing and Reimbursement Considerations
Some future improvements may need to be larger, deeper, or longer than required to serve an individual development project because they also provide regional benefit or serve upstream/downstream future development areas. These improvements may include oversized trunk storm drains, deeper storm drain segments, regional basin excavation, basin inlet/outlet structures, and downstream tie-ins needed to serve the ultimate drainage area.

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Where a development project is required to construct infrastructure that exceeds the capacity needed for that project alone, the City should evaluate whether the improvement is eligible for reimbursement, credit, cost sharing, or inclusion in a future funding mechanism. Eligibility should be based on whether the improvement provides benefit beyond the developing parcel, is consistent with the SWMP, serves an identified future tributary area, and is constructed to City standards.

For storm drain improvements not explicitly listed as a FCIP, the City may require a high-level oversizing evaluation during development review. The evaluation should compare the pipe size, depth, basin volume, or related infrastructure needed to serve the individual development against the improvement needed to serve the ultimate tributary area identified in the SWMP. Where detailed hydraulic cost allocation is not practical at the planning stage, the City may apply a percentage-based allocation or other planning-level method to estimate the regional oversizing share for use in reimbursement, credit, cost-sharing, or future funding mechanism decisions. The allocation should be refined during final design as pipe sizes, depths, quantities, ROW needs, and construction costs are better defined.

10.9 Cost Estimating and Funding Implementation
The FCIPs provide planning-level cost estimates for master planning, capital improvement programming, and funding/nexus study development. These estimates are not final construction estimates. Project-level costs should be updated during design to reflect current unit prices, survey, geotechnical information, utility conflicts, traffic control needs, ROW requirements, permitting, construction phasing, and final quantities.

Future CIP implementation should be coordinated with development timing, roadway improvements, utility projects, and land acquisition or easement needs. Where feasible, planned trunk storm drains should be installed with roadway or development projects to reduce reconstruction costs and improve implementation efficiency.

10.10 Deviations from the Master Plan
Deviations from the SWMP may be appropriate where updated development plans, grading, field conditions, utility conflicts, land availability, or other constraints make the planned configuration impractical. Any proposed deviation should be supported by a project-specific drainage study demonstrating that the revised configuration provides equivalent or improved performance compared with the SWMP concept.

At a minimum, the study should demonstrate that the proposed change does not increase flooding, reduce storage capacity, reduce downstream conveyance reliability, conflict with future regional infrastructure, or shift drainage impacts to adjacent properties or downstream facilities.

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10.11 Model Updates and Documentation
The Future Conditions model should be updated periodically as development occurs and as major drainage infrastructure is constructed. Development projects that construct master planned drainage facilities should provide record drawings, final pipe sizes and slopes, basin grading information, stage-storage data, outlet/control information, pump information, and updated drainage boundaries to support future model updates.

Maintaining an updated model will allow the City to track completed improvements, refine future project needs, confirm remaining capacity, and support future updates to capital improvement planning and drainage funding mechanisms.

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CHAPTER 11 RECOMMENDATIONS FOR FUTURE STUDIES
This chapter identifies recommendations for maintaining and implementing the SWMP after adoption.

The FCIPs developed in this SWMP provide a planning-level drainage framework for General Plan buildout; however, implementation will occur over time as development proceeds, funding becomes available, and project-specific design information is developed.

To keep the SWMP useful for City staff, development review, capital improvement planning, and funding decisions, it is recommended the City maintain a structured system for tracking proposed stormwater improvements, constructed infrastructure, model updates, project costs, and remaining drainage needs.

The recommendations in this chapter can be used to keep the SWMP current as an implementation tool, rather than to introduce new capital projects beyond those identified in Chapter 8.

11.1 Development Review Integration
It is recommended the City use the SWMP during development review to determine if proposed development is located within a tributary area served by a FCIP. Development applications could be reviewed against the planned drainage system to confirm whether the project is expected to construct, contribute to, or reserve space for master planned stormwater infrastructure.

Where a proposed development changes the assumed drainage pattern, outlet location, tributary area, or timing of a planned improvement, the applicant could then provide information on how these changes are incorporated in their project-specific drainage study to demonstrate that the proposed approach remains consistent with the SWMP.

11.2 Project Dependency and Phasing Review
Some FCIPs depend on downstream conveyance, regional storage, land availability, or other planned improvements. It is recommended the City track these dependencies so that projects are implemented in an order that supports system performance.

Before approving development that relies on a future regional stormwater improvement, the City would confirm whether the required downstream infrastructure is already in place, under design, funded, or still conceptual. Where downstream improvements are not yet available, interim storage or temporary drainage improvements could be required until permanent infrastructure is constructed.

11.3 As-Built and GIS Data Management
It is recommended the City require completed stormwater improvements to be documented with record drawings and GIS-ready asset information. This information can also be incorporated into the City’s master GIS system.

For storm drain projects, record information should include pipe diameter, material, length, slope, upstream and downstream invert elevations, rim elevations, manhole or junction structure locations, and tie-in information. For storage basin projects, record information should include basin footprint, grading surface, inlet and outlet structures, stage-storage relationship, access features, and maintenance-related

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appurtenances. For pump station or wet well improvements, record information should include pump curves, controls, wet well dimensions, operating elevations, discharge location, and electrical/mechanical equipment data.

11.4 Periodic SWMP Implementation Review
It is recommended the City perform a periodic SWMP implementation review to evaluate progress on proposed CIPs, completed development, constructed stormwater infrastructure, updated costs, and remaining drainage needs. This review could be completed annually or as part of the City’s capital improvement planning process.

At a minimum, the review should identify:

1. CIPs completed since the last review.

2. CIPs modified or replaced by development-driven improvements.

3. Projects that should be advanced because of active or anticipated development.

4. Projects that should be revised because of updated design information.

5. Model updates completed or still needed.

6. Cost estimate updates.

7. New drainage issues observed since adoption of the SWMP.

This recurring review will help keep the SWMP active as an implementation tool rather than a static planning document.

11.5 Future SWMP Updates
It is recommended this SWMP be updated periodically as major development occurs, as CIPs are constructed, as drainage assumptions change, and as City policies or regulatory requirements evolve.

At a minimum, future SWMP updates should incorporate completed stormwater infrastructure, updated development assumptions, revised FCIP scopes, updated cost estimates, observed system performance, and any changes to City drainage criteria or funding priorities.

During the next SWMP update, it is recommended the major drains be incorporated into the collection systems portion of the model. This will better reflect the impacts of the major drains on the City’s stormwater management infrastructure and vice versa.

Additionally, it is recommended that an existing surface cover layer be created to more accurately reflect the City’s surface cover at the time of the plan. The data utilized for this plan is an acceptable industry dataset. However, technology is being developed that can create vector-based geospatial data depicting actual surface cover (i.e. building roofs, sidewalks, driveways, landscaped areas, etc.)

11.6 Model Update Tracking
It is recommended the City maintains a log of model updates associated with completed projects, approved developments, revised drainage areas, and changes to stormwater infrastructure. The log would identify what changed, when it changed, who provided the information, and whether the Existing Conditions model, Future Base model, or Future Conditions with FCIPs model was updated.

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At a minimum, the model update tracking would include:

1. Constructed pipe sizes, lengths, slopes, and invert elevations.

2. Completed storage basin grading, footprint, and stage-storage information.

3. Pump and wet well information, including pump curves, on/off elevations, and discharge locations.

4. New or modified outfalls and tie-ins.

5. Updated subcatchment boundaries and land use assumptions.

6. Changes to FCIP limits, costs, or project descriptions.

7. Record drawing references and supporting design documents.

Maintaining this information will allow future SWMP updates to be more efficient as all the information is documented clearly in a single location.

11.7 Cost Update and Funding Support
It is recommended the planning-level costs developed in this SWMP be updated as projects move into design or as market conditions change.

Cost updates could identify whether changes are due to refined quantities, updated unit costs, added scope, ROW needs, utility conflicts, permitting requirements, construction phasing, or other project-specific factors. This information would support future capital improvement programming, development impact fee updates, reimbursement decisions, and financial nexus studies.

11.8 Aging Infrastructure and Culvert Replacement Planning It is recommended the City consider a systemwide repair and replacement assessment for aging storm drain infrastructure, including culverts, older trunk storm drains, pump stations, wet wells, and appurtenant structures.

The assessment would use available asset age, material, condition, maintenance history, hydraulic importance, and consequence of failure to identify facilities that may require future rehabilitation or replacement.

The results could be used to develop rough-order-of-magnitude replacement needs and support future storm service charge or capital funding updates.

11.9 Operations and Maintenance Cost Evaluation
It is recommended that as development occurs and additional stormwater infrastructure is constructed, the City periodically evaluate whether staffing, equipment, inspection frequency, pump station maintenance, basin maintenance, sediment removal, vegetation management, and emergency response resources remain adequate.

This evaluation would consider the additional operations and maintenance burden associated with future trunk storm drains, storage basins, pump facilities, and shared-use waterway coordination.

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11.10 CIP Tracking and Implementation Dashboard
A useful tool for the City’s stormwater program could be a stormwater CIP tracking dashboard or similar implementation tracking tool. The dashboard would be to provide a single, current location for tracking the status of Existing Conditions CIPs, FCIPs, development-driven drainage improvements, and related stormwater infrastructure updates.

If developed, at a minimum, the dashboard could track the following information for each project:

1. CIP number and project name.

2. Project type, such as storm drain, storage basin, pump/wet well, tie-in, or combined improvement.

3. Project location and associated drainage area.

4. Planning-level project description.

5. Current implementation status, such as planned, in design, under construction, completed, deferred, modified, or removed.

6. Estimated planning-level cost and most recent updated cost.

7. Funding source or anticipated funding mechanism, if known.

8. Development area or project trigger associated with the improvement.

9. Dependencies on other storm drains, basin, roadway, utility, or development projects.

10. Design documents, record drawings, and as-built information, once available.

11. Whether the SWMM model has been updated to reflect the completed improvement.

12. Notes on known constraints, including ROW, easements, utilities, land availability, or downstream tie-in limitations.

Additionally, the dashboard could be linked to GIS where practical so that project locations, drainage areas, basin sites, and trunk storm drain alignments can be viewed spatially.

This tool would help City staff quickly identify which improvements are associated with a proposed development, which projects have already been constructed, and which remaining improvements may be needed before additional development can be served.

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APPENDIX A AGREEMENT PROVISIONS BY FACILITY

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A.1 Overview
The City uses natural channels and ditches for stormwater conveyance, flood control, irrigation, and groundwater recharge. The following summarizes shared requirements across all partnering agencies.

A.1.1 Simultaneous Use
The City and agencies will coordinate to reduce flows if combined stormwater and irrigation/flood releases exceed channel capacity. Measures include adjusting City pump operations and redirecting flows through alternative channels. Costs for improvements to alternative channels are shared under separate agreements. These provisions do not modify flood release allocations defined elsewhere.

A.1.2 Development Review
Agencies may review tentative maps and development plans affecting creeks and channels. Comments are provided through the City’s Site Plan Review process, and the City will implement comments it concurs with. Disputes proceed to arbitration. Development along channels must dedicate land and easements for system expansion and maintenance.

A.1.3 Joint-use Facilities
If agencies participate in improvements, facilities may be designated joint-use under a separate agreement defining rights and obligations. Capacity created by City improvements is reserved for City discharges unless otherwise agreed.

A.1.4 Channel Maintenance
The City maintains channels within City limits, including vegetation removal, bank repairs, rip-rap, and all crossings. Agencies retain responsibility for headgates and may not increase inflow without City consent.

A.1.5 City Discharge Points
New discharge points require gates or controls. The City will provide location maps and operational details, comply with State/Federal discharge requirements, and prohibit sanitary sewage, industrial process water, or hazardous waste. Water leaving the City must remain suitable for irrigation and recharge.

A.1.6 Flow Monitoring
The City will monitor selected constituents at representative discharge locations and provide results to TID upon request.

A.1.7 Compliance
All activities must comply with applicable laws and agency regulations, including California Department of Fish and Game requirements.

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A.1.8 Replacement of Water
If City landscaping or channel modifications consume water otherwise available to agencies, the City will annually compensate for verified losses.

A.2 Individual Agreements
A.2.1 Mill Creek Agreement (KDWCD, 1993)
The City and the KDWCD entered an agreement on Mill Creek on July 8, 1993. Mill Creek is on the Lower Kaweah River and runs in a westerly direction through the City to a point where the channel divides into a north branch and main branch. The north branch runs in a westerly direction by the off-channel Goshen Pit, storage basin, and eventually into Cross Creek, which drains into Tulare Lake.

The main branch of Mill Creek runs in a southwesterly direction by the City's Sewage Treatment Plant and an off-channel storage basin owned by KDWCD, known as Basin No. 4, and eventually into Cross Creek, which drains into Tulare Lake. The agreement applies to the Mill Creek channel upstream of the point of division and the north branch and main branch downstream of the division.

KDWCD uses Mill Creek to transport water released from Lake Kaweah for flood control, irrigation, and other beneficial purposes. KDWCD also uses water from other sources downstream from Lake Kaweah through the City and beyond. The City uses Mill Creek as an integral part of the stormwater conveyance system and for other miscellaneous occurring surface waters collected within its boundaries.

A.2.1.1 Use of Mill Creek Channel
 Each party has the right to use the Mill Creek Channel for transporting waters.  Each party has the right to utilize, use, and enjoy all rights of access and rights-of-way owned by each party in the portion of the Mill Creek Channel east of the point of diversion for Basin No. 4. The access will be for the purpose of inspecting, repairing, and maintaining the channel by the appropriate party.  The City has the perpetual right to install and maintain crossings of Mill Creek, install and maintain discharge facilities in the banks of the channel, and to create open space amenities within City Limits.

Amenities could include parks, bike or walking paths, and recreation areas along the banks of Mill Creek.
 The City has the perpetual right within its boundaries to alter the course of Mill Creek Channel and to encase the channel by installation of a pipeline, pipelines, or other means.

A.2.1.2 Effect of Annexation of Lands to City
As the City annexes further lands, which include other portions of Mill Creek, the provisions of the agreement apply to the system as it is annexed to the City. No further agreement between the parties will be necessary to reflect the annexation, but as each annexation becomes final, the City shall file with KDWCD maps showing each such annexation affecting Mill Creek and stating the effective date of such annexation.

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A.2.2 Packwood Creek Agreement (TID/KDWCD, 1990)
Packwood Creek is a natural system originating on the Lower Kaweah River which runs southwesterly through the City and into the Tagus Basin in-channel storage facility owned by KDWCD, and eventually into Tulare Lake. The TID and KDWCD use Packwood Creek to transport water released from Lake Kaweah for flood control, irrigation, and other beneficial purposes, and Central Valley Project and other waters downstream to Tagus Basin and beyond.

The City uses Packwood Creek as an integral part of the stormwater system and for other miscellaneous occurring surface waters within its boundaries. User conflicts were resolved through an agreement dated September 10, 1990, with the following rights and requirements related to stormwater summarized below:

A.2.2.1 Use of Packwood Creek Channel
 The City has perpetual rights within City limits to install and maintain crossings of Packwood Creek, install and maintain discharge facilities in the banks, and to create open space amenities along the banks of Packwood Creek.
 The City has the perpetual right to alter the course of Packwood Creek Channel and to encase the same by installation of a pipeline or pipelines or other means within City boundaries.

A.2.3 Evans Ditch Agreement (EDC, 1993)
The City entered into an agreement with the Evans Ditch Company (EDC) on October 12, 1993 for the ownership and use of Evans Ditch. Evans Ditch is a manmade water course with a point of diversion from Mill Creek and runs generally southwesterly through the City and by an off-stream storage basin owned by KDWCD, referred to as Basin No. 13 and commonly known as Nelson Pit. EDC uses and utilizes Evans Ditch for diverting and transporting water released from Lake Kaweah for flood control, irrigation and other beneficial purposes, and waters from other sources downstream from Lake Kaweah through the City and beyond. The City utilizes Evans Ditch for conveying stormwater. The agreement details specific requirements for each party. General terms of the agreement are covered in Section 2.8.1 and specifics for Evans Ditch are provided in the following sections.

A.2.3.1 Ownership and Use of Evans Ditch Channel
EDC granted a Quit Claim Deed to the City for an undivided one-half (1/2) interest in and to the Evans Ditch channel and right-of-way within the city limits. The quitclaim is for rights to transport City stormwater runoff and other miscellaneous surface waters through Evans Ditch to off-line basins and to maintain the Evans Ditch. The quitclaim is exclusive of Evans Ditch’s headgate and diversion facilities. The rights to be conveyed by EDC to the City are subordinate and inferior to Evan Ditch’s established right to transport waters.

The City will has the perpetual right within City limits to install and maintain crossings of Evans Ditch, install and maintain discharge facilities in the banks, and to create open space amenities. Additionally, the City has the right within its boundaries to alter the course of the Evans Ditch channel and to encase the same by installation of a pipeline, or pipelines, or other means as long as the alteration or piping of the channel does not interfere with Evan Ditch’s use of the channel or the delivery of water to its shareholders.

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A.2.4 Modoc Ditch Agreement (MDC, 2016)
On March 11, 2016, the City and the Modoc Ditch Company (MDC) entered into an agreement regarding the use of Modoc Ditch (Modoc Ditch Company/City of Visalia, 2016). The agreement terminated all pre-existing agreements concerning the use of Modoc Ditch, including but not limited to the agreement of December 12, 1992. The agreement merged the other agreements into the 2016 Agreement as the sole expression of City’s rights to the use and control of Modoc Ditch. The agreement contains the mutual and reciprocal rights, duties, and obligations of each of the parties to use Modoc Basin, the SK Ranch/Vander Stelt Basin Site and other related facilities. The following discussion summarizes key points related to the discharge of stormwater into the ditch, connection points, and coordination for stormwater operations along Modoc Ditch. The sections maintain the numbering within the agreement for ease of finding the full information in the referenced agreement.

A.2.4.1 Quitclaim by MDC of Interest in Modoc Ditch
MDC forever quitclaimed to the City an undivided one-third (1/3) interest in and to Modoc Ditch. The conveyance is exclusive of Modoc Ditch’s headgate on the St. John’s River and non-City diversion facilities, except such diversion facilities necessary to divert water to City property. The City rights of use of the one- third (1/3) interest in Modoc Ditch are defined in the agreement as follows:
 The City’s right to use Modoc Ditch Channel shall generally be confined to the right to introduce and transport City stormwater runoff, or other water under the control of the City, from the point of introduction to a suitable point of disposal determined by the City and to access all of Modoc Ditch to for this use.
 The City cannot abandon City water in the Modoc Ditch Channel, and is responsible for prompt disposal of any introduced City water into the terminal basin facilities or other disposal or recharge facilities, except for seepage losses during transportation.  The City has the right to use the Modoc Ditch channel for transportation of City water to the full capacity of Modoc Ditch Channel, but such use at all times, other than as specifically provided below, is subordinate and inferior to MDC’s established right to transport waters in and along Modoc Ditch Channel. The City has the primary and superior right to 54 cfs capacity in the Modoc Ditch Channel between October 1 of any year and May 1 of the following year, and a subordinate right, subject to MDC’s prior right, to the balance of the capacity of the Modoc Ditch Channel.  If the MDC makes improvements to the SK Ranch/Vander Stelt Basin Site to meet all of MDC’s entitled flood release flows between October 1 to May 1, the City can use the full capacity of the Modoc Ditch Channel for stormwater conveyance and disposal. The stormwater must be evacuated through diversion or seepage prior to the need for MDC to resume use of the Modoc Ditch Channel.  MDC, at its cost, is solely responsible for maintaining the Modoc Ditch Channel, exclusive of any City- installed and maintained pedestrian, bike, or park facilities.  The City has the right to install and maintain any discharge and diversion facilities on Modoc Ditch as long as the installation does not interfere with MDC’s use of the Modoc Ditch Channel. Details must be forwarded to MDC for approval.
 No portion of the Modoc Ditch Channel can be abandoned without consent and approval of both MDC and the City.

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A.2.4.2 Use by MDC of City Facilities
During the months of June through October of each year, MDC shall have the right to use Modoc Basin, or any remnant of Modoc Basin, for MDC’s water balancing and/or recharge purposes under the following conditions:
 The MDC shall be permitted to divert water to Modoc Basin for water regulating or seasonal storage only to the extent that such diversions will not cause the water level in Modoc Basin to exceed a level that is equal to seven feet below the invert level of Modoc Ditch at the northeasterly point of introduction into Modoc Basin. This provision is intended to maintain, at all times, a certain minimum storage capacity available to City for layoff of water or disposal of unanticipated stormwater flows or nuisance flows.
 The City can modify the Modoc Basin regardless of whether the modification has the effect of diminishing, or eliminating the utility of the Modoc Basin for use by MDC.  MDC’s use of the Modoc Basin for water balancing and/or recharge does not constitute a bank, and MDC cannot recover any water recharged to the underlying groundwater aquifer as a result of MDC’s use of the basin. MDC can recognize the groundwater benefit or credit under the provisions of a Groundwater Sustainability Plan in furtherance of the Sustainable Groundwater Management Act, or other similar regulatory or adjudicatory plan if MDC is able to establish entitlement to the benefit or credit.
 The City cannot use any water introduced by MDC into Modoc Basin unless agreed in writing between the parties. The City shall allow MDC to pump such water out of Modoc Basin when and in the amounts as determined by MDC, unless retaining such water in Modoc Basin violates some other provision of the Agreement.
 The City is not be obligated to compensate MDC for any water introduced by MDC into the Modoc Basin that recharges the groundwater aquifer underlying the Basin unless there is a written agreement between MDC and the City.
 MDC will waive any abandonment fee in relation to a request to abandon any portion of the Modoc Ditch facilities not located, based on the terms in the agreement.  The City owns and operates the Shannon Ranch Basin, and has allowed the basin to be used by MDC as a water regulating and temporary storage site for MDC water when the use does not interfere with the City’s use. MDC continues to have the right to introduce water to Shannon Ranch Basin. MDC, or St. John’s Ditch Company as assignee of MDC, will continue to have the right to maintain a pump at the northwest corner of Shannon Ranch Basin to remove any water introduced by MDC or St. John’s Ditch Company into the Shannon Ranch Basin. This will use will be limited to the months of June through October of each year.

A.2.4.3 City Use of SK Ranch/Vander Stelt Basin Site
The City has the right to divert City water into the SK Ranch/Vander Stelt Basin Site for the purpose of groundwater recharge, subject to the following conditions:
 City use cannot interfere with MDC’s use of the SK Ranch/Vander Stelt Basin Site.  The City must provide reasonable written notice to MDC of its intent to divert water into the SK Ranch/Vander Stelt Basin Site. The notice must include the intended diversion rate, duration, and

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quantity. The diversion cannot begin until MDC has confirmed that the intended diversion can be accommodated.
 MDC has the right to allow diversion of water into the SK Ranch/Vander Stelt Basin Site by KDWCD prior to approving any diversion by the City of City water into the basin.

The City’s diversions at the SK Ranch/Vander Stelt Basin Site are limited to the diversion capacities through the structures or facilities at the time of the intended diversion. The City cannot, without prior approval by MDC, make any improvements or install any structures or facilities to increase the diverted water onto the SK Ranch/Vander Stelt Basin Site.

The City may account for its use of the SK Ranch/Vander Stelt Basin as a beneficial use of water for groundwater recharge. However, the basin does not constitute a bank, and the City is not entitled to directly recover any water recharged to the underlying groundwater aquifer as a result of City’s use of the basin.

A.2.5 Persian Ditch Agreement (PDC, 1993)
The City entered into an agreement with the Persian Ditch Company (PDC) on June 3, 1993 for the ownership and use of Persian Ditch. Persian Ditch is a manmade water course with a point of diversion from Mill Creek. PDC uses and utilizes Persian Ditch for diverting and transporting water released from Lake Kaweah for flood control, irrigation and other beneficial purposes, and waters from other sources downstream from Lake Kaweah through the City and beyond. The City utilizes Persian Ditch for conveying stormwater. The agreement details specific requirements for each party. General terms of the agreement are covered in Section 2.8.1 and specifics for Persian Ditch are provided in the following sections.

A.2.5.1 Ownership and Use of Persian Ditch Channel
PDC granted a Quit Claim Deed to the City for an undivided one-third (1/3) interest in and to the Persian Ditch channel and right-of-way within the city limits. The quitclaim is for rights to transport City stormwater runoff and other miscellaneous surface waters through Persian Ditch to off-line basins and to maintain the Persian Ditch. The quitclaim is exclusive of Persian Ditch’s headgate and diversion facilities.

The rights to be conveyed by PDC to the City are subordinate and inferior to Persian Ditch’s established right to transport waters.

The City will has the perpetual right within city limits to install and maintain crossings of Persian Ditch, install and maintain discharge facilities in the banks, and to create open space amenities. In addition, the City has the right within its boundaries to alter the course of the Persian Ditch channel and to encase the same by installation of a pipeline, or pipelines, or other means as long as the alteration or piping of the channel does not interfere with Persian Ditch’s use of the channel or the delivery of water to its shareholders.

A.2.6 Watson Ditch Agreement (WDC, 1993)
The City entered into an agreement with the Watson Ditch Company (WDC) on June 3, 1993 for the ownership and use of Watson Ditch. Watson Ditch is a manmade water course with a point of diversion from Mill Creek. WDC uses and utilizes Watson Ditch for diverting and transporting water released from Lake Kaweah for flood control, irrigation and other beneficial purposes, and waters from other sources

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downstream from Lake Kaweah through the City and beyond. The City utilizes Watson Ditch for conveying stormwater. The agreement details specific requirements for each party.

A.2.6.1 Ownership and Use of Watson Ditch Channel
WDC granted a Quit Claim Deed to the City for an undivided one-third (1/3) interest in and to the Watson Ditch Channel and right-of-way within the city limits. The quitclaim is for rights to transport City stormwater runoff and other miscellaneous surface waters through Watson Ditch to off-line basins and to maintain the Watson Ditch. The quitclaim is exclusive of Watson Ditch’s headgate and diversion facilities.

The rights to be conveyed by WDC to the City are subordinate and inferior to Watson Ditch’s established right to transport waters.

The City has the perpetual right within City limits to install and maintain crossings of Watson Ditch, install and maintain discharge facilities in the banks, and to create open space amenities. In addition, the City has the right within its boundaries to alter the course of the Watson Ditch Channel and to encase the same by installation of a pipeline, or pipelines, or other means as long as the alteration or piping of the channel does not interfere with Watson Ditch’s use of the channel or the delivery of water to its shareholders.

A.2.7 Tulare Irrigation Canal Agreement
The City entered into an agreement with the Tulare Irrigation Company (TIC) on June 18, 1991 for the ownership and use of Tulare Irrigation Canal. Tulare Irrigation Canal is a manmade water course with a point of diversion from the Lower Kaweah River and runs southwesterly until it crosses the Atchison, Topeka, and Santa Fe (AT&SF) Railroad line along Road 128 (Santa Fe Avenue) and flows south to its confluence with Cameron Creek. TIC uses Tulare Irrigation Canal for diverting and transporting water released from Lake Kaweah for flood control, irrigation and other beneficial purposes, and waters from other sources downstream from Lake Kaweah through the City and beyond. The City utilizes Tulare Irrigation Canal for conveying stormwater. The agreement details specific requirements for each party.

General terms of the agreement are covered in Section 2.8.1 and specifics for Tulare Irrigation Canal are provided in the following sections.

A.2.7.1 Ownership and Use of Tulare Irrigation Canal
TIC granted a Quit Claim Deed to the City for an undivided one-third (1/3) interest in and to the Tulare Irrigation Canal channel and right-of-way within the city limits. The quitclaim is for rights to transport City stormwater runoff and other miscellaneous surface waters through Tulare Irrigation Canal to off-line basins and to maintain the Tulare Irrigation Canal. The quitclaim is exclusive of Tulare Irrigation Canal’s headgate and diversion facilities. The rights to be conveyed by TIC to the City are subordinate and inferior to Tulare Irrigation Canal established right to transport waters.

The City has the perpetual right within City limits to install and maintain crossings of Tulare Irrigation Canal, install, and maintain discharge facilities in the banks, and to create open space amenities. In addition, the City has the right within its boundaries to alter the course of the Tulare Irrigation Canal channel and to encase the same by installation of a pipeline, or pipelines, or other means as long as said alteration or piping of the channel does not interfere with Tulare Irrigation Canal’s use of the channel or the delivery of water to its shareholders.

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY

APPENDIX B STORM DRAINAGE DESIGN CRITERIA
Storm Drainage Design Criteria is currently being updated by the City. The updated criteria should be requested from the City for any projects within the City.

STORM DRAINAGE DESIGN CRITERIA
LIEM.

MINOR (COLLECTOR) DRAINS

MAJOR DRAINS

IN- TOWN DETENTION BASINS

IN- TOWN RETENTION BASINS

LEVEL OF PROTECTION
VOLUME
N/A
N/A
10 YEAR - 1 DAY
10 YEAR - 10 DAY

INDUSTRIAL PARK RETENTION BASINS

DOWNSTREAM ULTIMATE STORAGE BASINS
10 YEAR - 10 DAY
10 DAY - 50 YEAR
NOTES:

LEVEL OF PROTECTION
2 YEAR
10 YEAR
10 YEAR - 10 DAY
10 YEAR - 10 DAY
10 YEAR - 10 DAY
10 DAY - 50 YEAR

1. MAJOR DRAINS GENERALLY SERVE AREAS IN EXCESS OF 100 ACRES. THESE DRAINS ARE DEFINED AND ANAL Y2ED IN THE CITY'S STORM WATER MASTER PLAN.

2. MINOR DRAINS CONVEY RUNOFF TO THE MAJOR DRAINS AND GENERALLY SERVE AREAS LESS THAN 100 ACRES.

3. THE STORAGE VOLUME FOR DETENTION STORAGE IS BASED ON A 10-YEAR, 1-DAY STORM EVENT WITH A TOTAL RAINFALL OF 2.09 INCHES. THE BASIN SHALL ALSO ACCOMMODATE A 10-YEAR, 2-DAY EVENT WITH A TOTAL RAINFALL OF 2.64 INCHES WITH FREEBOARD AND PUMPING TAKEN INTO ACCOUNT. THE MAXIMUM DESIGN DEPTH AND SIDE SLOPES OF THE BASIN MUST BE APPROVED BY THE CITY. DISCHARGE PUMPS WITH A CITY APPROVED CAPACITY SHALL BE INSTALLED AND OPERATED IN ACCORDANCE WITH CITY STORM WATER DISCHARGE POLICIES.

4. THE STORAGE VOLUME FOR RETENTION STORAGE IS BASED ON A 10-YEAR, 10-DAY STORM EVENT WITH A TOTAL RAIN FALL OF 4.17 INCHES. DISCHARGE PUMPS CAN ONLY BE INSTALLED AND OPERATED WITH THE APPROVAL OF THE CITY.

5. THE DESIGN WATER SURFACE ELEVATION IN A BASIN SHALL BE A MINIMUM OF ONE FOOT BELOW THE LOWEST CATCH BASIN IN THE AREA THAT IS TRIBUTARY TO THE BASIN.

6. THE CITY DOES NOT CONSIDER PERCOLATION/INFILTRATION FACTORS IN SIZING BASINS.

RATIONAL METHOD RUNOFF COEFFICIENTS

AND DESIGN CRITERIA FOR STORM WATER BASINS

COEFFICIENT OF STORAGE VOLUME

LAND USE RUNOFF (C) (ACRE-FEET/ACRE)
DETENTION RETEN]Ot:!
INDUSTRIAL AND COMMERCIAL 0.85 0.148 0.295
PROFESSIONAL OFFICE 0.65 0.113 0.226

RESIDENTIAL
- HIGH DENSITY (15-29 UNITS/ACRE) 0.55 0.096 0.191
- MEDIUM DENSITY (11-14 UNITS/ACRE) 0.45 0.078 0.156
- LOW DENSITY (3-10 UNITS/ACRE) 0.35 0.061 0.122
- RURAL ( 1-2 UNITS/ACRE) 0.30 0.052 0.104
PUBLIC/INSTITUTIONAL 0.40 0.070 0.139

OPEN SPACE
- IMPROVED (PARKS) 0.25 0.044 0.087
- UNIMPROVED 0.15 0.026 0.052

DESIGN CRITERIA

1. THE RATIONAL METHOD MAY BE USED TO DETERMINE PEAK FLOWS AND RUNOFF VOLUMES FOR AREAS LESS THAN 150 ACRES.

2. ALL NEW DEVELOPMENTS SHALL BE DESIGNED SUCH THAT THE SURFACE OF PONDED WATER DURING THE 100-YEAR RAINFALL EVENT DOES NOT RISE MORE THAN ONE FOOT ABOVE THE LOWEST TOP OF CURB IN THE DEVELOPMENT.

3. LOT TO STREET TIME = 25 MINUTES. (RESIDENTIAL ONLY)

4. GUTTER VELOCITY = 2 FEET PER SECOND.
'14' ~ CITY OF VISALIA
APPROVED BY: ~ 1734~ 09~~~16 DESIGN & IMPROVEMENT STANDARDS

DESIGN CRITERIA FOR DRAINAGE

REVISIONS
06/14/13
BK 2016
D-36
2 YEAR ---------
5 YEAR ---------
10 YEAR
25 YEAR ················································· 50 YEAR - - - - -

3.50 ' " ' '\

3.00 \.
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0.00 5 10 15 30 60 120 180

DURATION - MINUTES
APPROVED BY: ~ ~ CITY OF VISALIA
09/16/16 DESIGN & IMPROVEMENT STANDARDS CITY ENGINEER R.P.E. 81734 DATE

REVISIONS
INTENSITY DURATION CURVES 06/18/04 D-35
BK 2016

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY

APPENDIX C EXISTING CONDITIONS HYDROLOGIC

PARAMETERS

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) S0 12.83 89 3,653 0.020
S1 67.59 88 22,303 0.104
S10 14.50 89 6,134 0.383
S100 8.59 82 2,994 0.221
S101 23.81 89 8,295 0.380
S102 8.91 87 3,106 0.260
S103 2.75 89 957 0.435
S104 16.56 89 5,772 0.190
S105 10.68 88 3,720 0.253
S106 5.43 89 1,893 0.051
S107 6.75 89 2,351 0.342
S108 6.91 89 2,406 0.342
S109 82.30 89 28,679 0.330
S11 161.37 87 70,294 0.261
S110 6.95 89 2,422 0.190
S111 6.22 89 2,167 0.170
S112 7.31 86 2,548 0.128
S113 19.69 87 6,860 0.426
S114 7.12 84 2,482 0.699
S115 49.27 85 17,171 0.629
S116 31.41 89 10,947 0.159
S117 100.25 87 34,936 0.248
S118 104.39 90 45,473 0.261
S119 46.19 91 20,118 0.160
S12 41.52 84 7,697 0.316
S120 18.92 90 8,242 0.270
S121 81.51 90 35,505 0.212
S122 25.29 85 8,814 0.296
S123 3.91 87 1,704 0.205
S124 17.84 85 6,216 0.255
S125 34.73 84 12,104 0.310
S126 11.51 83 4,010 0.399
S127 14.35 89 5,000 0.296
S128 15.42 87 6,718 0.229
S129 6.08 86 2,650 0.320
S13 45.58 88 18,051 0.326
S130 35.92 84 15,644 0.175
S131 1.65 83 717 0.554
S132 13.74 87 5,985 0.381
S133 12.66 84 5,513 0.582
S134 13.38 89 4,662 0.339
Table C-1. Existing Conditions Hydrologic Parameters

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-1

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S135 72.92 84 25,411 0.448
S136 21.78 85 7,589 0.414
S137 11.03 84 3,844 0.318
S138 4.84 86 1,686 0.492
S139 17.78 86 6,195 0.713
S14 20.08 86 1,749 0.197
S140 10.73 84 3,740 1.048
S141 9.61 84 3,349 0.382
S142 10.56 83 3,681 0.170
S143 13.29 66 1,158 0.353
S144 1.24 89 1,805 0.181
S145 31.80 88 11,080 0.194
S146 87.12 84 30,359 0.410
S147 45.91 88 15,997 0.190
S148 14.49 89 5,051 0.193
S149 57.44 85 20,017 0.192
S15 17.81 90 7,533 0.399
S150 5.75 82 2,004 0.312
S151 6.04 83 2,104 0.335
S152 1.91 83 664 0.461
S153 18.56 82 6,466 0.260
S154 28.06 89 9,777 0.280
S155 67.89 84 23,657 0.188
S156 6.63 82 2,312 0.529
S157 5.56 84 1,937 0.185
S158 8.61 83 2,999 0.362
S159 2.64 83 920 0.402
S16 3.50 74 3,814 1.158
S160 17.28 83 6,021 0.463
S161 60.40 82 21,048 0.298
S162 24.39 83 8,499 0.352
S163 7.20 69 2,509 0.586
S164 14.25 88 4,966 0.129
S165 21.24 84 7,400 0.336
S166 25.07 88 8,737 0.293
S167 47.58 83 16,580 0.305
S168 6.20 84 2,161 0.252
S169 4.98 84 1,734 0.020
S17 19.35 86 6,433 0.849
S170 49.21 84 17,149 0.296
S171 3.88 84 1,352 0.247

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-2

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S172 22.71 82 1,979 0.084
S173 18.14 85 6,322 0.235
S174 7.01 84 2,441 0.568
S175 26.65 84 9,288 0.233
S176 13.57 89 4,728 0.181
S177 8.35 88 727 0.992
S178 40.30 84 14,044 0.243
S179 4.47 86 1,556 0.020
S18 10.82 89 4,171 0.331
S180 9.90 87 3,451 0.020
S181 2.25 82 784 0.020
S182 10.73 89 3,740 0.240
S183 22.51 89 7,845 0.026
S184 42.27 92 14,731 0.232
S185 4.24 88 1,479 0.217
S186 42.99 87 3,745 0.308
S187 38.41 83 13,385 0.284
S188 22.97 88 8,006 0.110
S189 20.61 87 7,182 0.159
S19 39.61 82 3,451 0.250
S190 43.96 84 15,319 0.259
S191 1.76 89 2,552 0.020
S192 88.12 85 30,709 0.183
S193 34.26 87 11,940 0.358
S194 24.78 83 8,634 0.559
S195 42.86 88 14,937 0.291
S196 13.51 84 4,708 0.341
S197 10.65 86 3,710 0.265
S198 18.82 86 1,639 0.226
S199 18.55 91 1,616 0.367
S2 10.75 88 4,335 0.185
S20 11.81 89 3,726 0.158
S200 8.93 81 7,776 1.548
S201 33.00 83 11,500 0.180
S202 23.26 83 3,377 0.247
S203 80.17 85 27,936 0.200
S204 38.79 82 3,380 0.378
S205 33.91 87 3,693 0.430
S206 21.15 68 1,843 0.390
S207 6.70 55 584 0.539
S208 8.56 85 2,984 0.259

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-3

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S209 64.24 87 22,386 0.263
S21 28.23 84 2,999 0.247
S210 17.07 84 5,949 0.187
S211 9.53 83 3,320 0.504
S212 37.58 82 8,185 0.326
S213 20.14 89 4,387 0.058
S214 41.29 87 14,390 0.219
S215 34.21 84 11,921 0.337
S216 23.22 82 5,058 0.355
S217 14.17 87 4,937 0.301
S218 30.43 87 10,603 0.289
S219 18.27 89 6,367 0.232
S22 2.86 87 1,038 0.317
S220 13.05 88 4,546 0.347
S221 13.69 87 1,704 0.659
S222 93.16 83 32,464 0.277
S223 4.78 89 1,664 0.516
S224 2.44 88 817 0.172
S225 3.81 90 1,659 0.492
S226 71.58 89 31,181 0.277
S227 3.40 90 1,481 0.344
S228 42.13 90 18,350 0.421
S229 8.73 84 3,042 0.209
S23 2.77 85 1,298 0.243
S230 14.68 82 5,115 0.365
S231 14.64 83 5,103 0.230
S232 13.52 84 4,711 0.306
S233 1.43 56 2,497 0.020
S234 6.99 82 2,437 0.237
S235 14.64 82 5,100 0.219
S236 25.56 81 8,907 0.252
S237 4.98 84 1,735 0.463
S238 16.55 87 1,442 0.569
S239 34.28 85 11,945 0.528
S24 7.61 84 2,351 0.285
S240 10.13 84 3,529 0.045
S241 9.38 68 817 0.374
S242 3.77 81 522 0.020
S243 20.82 56 1,814 0.771
S244 25.52 60 2,223 0.557
S245 9.00 85 3,135 0.304

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-4

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S246 9.67 45 842 0.109
S247 37.04 83 12,908 0.482
S248 127.96 86 11,148 0.514
S249 68.94 88 8,580 0.429
S25 19.87 88 7,153 0.308
S250 51.16 72 4,457 0.393
S251 67.27 82 23,442 0.914
S252 21.39 84 7,453 0.817
S253 31.39 89 10,939 0.403
S254 45.08 87 15,708 0.346
S255 27.58 88 9,613 0.748
S256 9.52 80 8,290 1.280
S257 7.61 87 2,650 0.355
S258 32.01 89 11,154 0.401
S259 42.35 84 14,760 0.310
S26 36.10 89 13,216 0.391
S260 7.95 84 2,772 0.388
S261 29.29 84 10,208 0.238
S262 15.82 88 5,514 0.480
S263 26.39 86 9,195 0.293
S264 11.09 88 3,865 0.224
S265 8.04 89 2,803 0.332
S266 9.41 89 3,279 0.293
S267 26.41 88 9,202 0.365
S268 12.15 89 5,292 0.502
S269 7.03 76 6,122 0.701
S27 21.34 89 8,452 0.434
S270 46.44 81 11,560 0.682
S271 21.70 89 9,454 0.542
S272 10.88 91 4,739 0.448
S273 30.43 90 13,257 0.339
S274 68.04 90 29,639 0.296
S275 31.81 83 11,086 0.368
S276 16.69 88 5,815 0.209
S277 14.14 84 2,053 0.323
S278 7.14 87 2,486 0.266
S279 14.43 81 5,030 0.303
S28 15.54 89 6,445 0.361
S280 32.22 88 11,230 0.297
S281 2.94 83 1,025 0.020
S282 12.96 83 4,516 0.224

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-5

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S283 22.19 81 4,833 0.439
S284 19.56 87 6,816 0.211
S285 15.47 81 5,391 0.377
S286 197.46 88 68,811 0.387
S287 69.17 86 24,105 0.594
S288 12.98 84 4,523 0.537
S289 11.86 88 2,066 0.136
S29 36.95 89 12,876 0.300
S290 130.82 86 45,588 0.254
S291 204.25 88 71,175 0.255
S292 190.91 89 66,528 0.263
S293 60.07 62 5,233 0.205
S294 25.67 84 8,945 0.188
S295 35.82 84 12,484 0.292
S296 1.97 84 686 0.186
S297 157.85 62 13,752 0.233
S298 24.30 84 8,468 0.229
S299 5.01 82 1,747 0.636
S3 25.33 89 8,173 0.223
S30 6.18 89 2,152 0.346
S300 16.60 83 5,785 0.743
S301 24.69 81 8,605 0.318
S302 10.93 84 4,762 1.083
S303 23.47 86 10,223 0.221
S304 36.47 85 12,708 0.230
S305 4.36 82 1,519 1.413
S306 13.30 83 4,635 0.562
S307 26.68 82 9,296 0.480
S308 25.93 85 9,037 0.345
S309 38.30 88 13,347 0.256
S31 10.11 89 3,521 0.773
S310 23.21 85 8,090 0.383
S311 45.25 83 15,769 0.317
S312 14.45 88 5,036 0.073
S313 10.17 86 3,545 0.291
S314 9.22 87 3,212 0.020
S315 4.18 84 1,455 0.020
S316 6.33 83 2,205 0.097
S317 28.33 85 9,873 0.287
S318 73.81 88 25,721 0.417
S319 30.26 77 2,636 0.258

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-6

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S32 17.05 88 1,486 1.519
S320 31.51 88 10,980 0.167
S321 18.66 85 5,420 0.288
S322 53.62 84 18,686 0.020
S323 5.48 83 1,911 0.305
S324 13.12 88 4,573 0.906
S325 11.85 89 4,131 0.179
S326 12.64 84 4,404 0.109
S327 48.42 82 16,874 0.528
S328 9.38 89 3,267 0.398
S329 23.96 89 8,349 0.276
S33 16.68 89 5,812 0.287
S330 16.04 89 5,589 0.338
S331 9.34 89 3,255 0.990
S332 4.67 88 4,065 1.486
S333 40.32 89 14,049 0.396
S334 41.19 89 14,355 0.207
S335 36.19 89 12,612 0.344
S336 14.34 88 4,998 0.020
S337 40.61 89 14,153 0.187
S338 41.69 88 14,529 0.319
S339 64.74 87 22,562 0.319
S34 4.24 89 1,476 0.374
S340 71.84 81 25,034 0.196
S341 17.31 70 7,539 2.513
S342 2.28 83 794 1.634
S343 3.68 83 1,281 0.788
S344 57.86 83 20,164 0.253
S345 18.03 87 6,281 0.384
S346 66.99 88 23,344 0.315
S347 35.62 86 12,411 0.105
S348 22.54 87 7,854 0.154
S349 11.73 88 4,087 0.020
S35 15.67 89 5,459 0.343
S350 72.50 89 25,264 0.260
S351 53.52 88 18,651 0.124
S352 116.60 88 25,396 0.251
S353 76.58 86 16,679 0.217
S354 44.09 88 15,363 0.284
S355 4.70 89 1,638 0.143
S356 2.68 89 935 0.217

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-7

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S357 8.53 88 2,974 0.181
S358 28.20 86 9,825 0.235
S359 16.10 88 5,612 0.214
S36 23.50 89 8,189 0.332
S360 8.00 89 2,787 0.429
S361 28.08 84 9,785 0.301
S362 23.63 84 8,234 0.331
S363 25.40 82 8,852 0.469
S364 39.87 86 13,892 0.497
S365 29.18 81 6,356 0.165
S366 23.57 87 8,214 0.217
S367 23.04 81 8,031 0.494
S368 24.14 84 8,411 0.196
S369 14.99 81 5,225 0.673
S37 15.92 89 5,549 0.221
S370 12.02 89 5,235 0.337
S371 11.90 78 1,037 0.020
S372 0.18 89 780 0.020
S373 13.75 87 4,793 0.314
S374 0.27 88 1,195 0.020
S375 32.36 89 11,278 0.291
S376 33.39 83 9,696 0.166
S377 168.88 74 14,713 0.302
S378 16.66 81 5,805 0.420
S379 3.67 81 3,193 0.545
S38 16.74 89 5,833 0.347
S380 72.54 84 25,277 0.334
S381 4.47 81 1,299 1.135
S382 43.42 63 6,877 0.791
S383 33.92 84 2,955 0.210
S384 8.59 81 748 0.215
S385 14.59 84 5,083 0.673
S386 30.43 84 10,605 0.272
S387 94.80 88 33,034 0.260
S388 37.40 88 13,034 0.143
S389 3.02 89 1,052 0.077
S39 33.77 88 11,768 0.296
S390 15.54 88 5,414 0.097
S391 13.76 86 5,992 0.493
S392 5.82 76 4,222 1.202
S393 25.46 89 8,872 0.263

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-8

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S394 18.12 81 1,579 0.227
S395 51.09 66 4,451 1.664
S396 53.09 84 8,660 0.395
S397 39.09 85 13,621 0.225
S398 67.40 87 23,487 0.329
S399 10.36 87 9,025 1.238
S4 12.08 89 4,209 0.141
S40 42.18 86 14,700 0.271
S400 62.50 88 21,780 0.249
S401 112.38 88 39,163 0.259
S402 16.91 88 14,732 0.354
S403 35.02 88 12,203 0.296
S404 1.26 88 1,098 0.461
S405 1.51 83 1,318 0.020
S406 1.87 89 1,630 0.020
S407 2.79 89 973 0.020
S408 9.36 84 3,262 0.661
S409 4.54 88 1,318 0.020
S41 23.86 88 8,314 0.315
S410 6.22 74 27,112 0.556
S411 64.04 88 27,897 0.355
S412 42.13 86 14,681 0.387
S413 17.01 89 5,927 0.409
S414 8.40 89 2,925 0.372
S415 4.74 89 1,653 0.212
S416 27.71 81 2,414 0.191
S417 35.40 81 3,084 0.168
S418 40.17 81 3,500 0.194
S419 16.72 81 2,914 0.325
S42 5.67 87 1,976 0.256
S420 99.33 81 8,653 0.572
S421 29.33 81 2,555 0.075
S422 4.15 87 3,616 0.020
S423 21.04 84 1,833 0.329
S424 17.85 85 7,773 0.322
S425 28.37 82 9,885 0.506
S426 18.81 82 6,555 0.302
S427 8.79 81 851 1.707
S428 13.90 85 1,211 0.513
S429 68.81 85 23,979 0.184
S43 7.19 79 3,197 0.989

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-9

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S430 41.59 87 14,492 0.214
S431 16.45 81 2,866 0.415
S432 17.15 89 5,978 0.438
S433 64.35 88 22,425 0.224
S434 11.18 85 3,895 0.161
S435 6.84 88 2,385 0.038
S436 77.71 88 27,081 0.251
S437 5.67 89 1,977 0.286
S438 13.73 87 4,783 0.145
S439 55.95 84 9,749 0.118
S44 4.52 87 1,575 0.387
S440 19.96 86 6,955 0.314
S441 19.31 87 6,730 0.247
S442 37.58 88 13,094 0.310
S443 5.80 89 2,022 0.163
S444 41.74 82 14,547 0.313
S445 57.39 87 20,000 0.342
S446 15.27 87 5,322 0.452
S447 21.23 90 9,248 0.240
S448 29.37 91 12,795 0.606
S449 19.48 90 8,484 0.306
S45 75.63 87 26,356 0.276
S450 4.45 90 1,938 0.374
S451 14.06 89 6,123 0.330
S452 14.34 92 6,247 0.199
S453 20.04 91 8,727 0.425
S454 38.93 92 16,959 0.998
S455 25.87 91 11,268 1.064
S456 4.46 84 1,555 0.400
S457 77.11 84 26,870 0.239
S458 9.19 91 4,002 0.150
S459 10.60 84 9,235 1.476
S46 35.60 83 12,407 0.308
S460 32.49 87 11,323 0.889
S461 19.22 88 6,698 0.355
S462 20.78 87 7,240 0.403
S463 38.39 88 3,344 0.456
S464 48.44 74 4,220 0.273
S465 27.40 91 11,936 0.332
S466 9.37 81 3,264 0.130
S467 35.47 81 12,361 0.393

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-10

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S468 7.04 84 2,452 0.327
S469 9.06 84 3,158 0.340
S47 15.15 88 5,279 0.507
S470 26.01 83 9,062 0.441
S471 36.40 84 12,686 0.307
S472 22.84 90 9,948 0.541
S473 18.77 91 8,176 0.807
S474 4.69 89 2,042 0.481
S475 5.96 86 519 0.273
S476 13.97 82 4,867 0.242
S477 26.15 84 9,114 0.465
S478 32.83 83 7,150 0.401
S479 5.43 89 2,363 0.215
S48 13.26 88 3,208 0.218
S480 103.79 87 36,169 0.256
S481 12.60 89 4,389 0.773
S482 34.96 89 12,183 0.377
S483 121.40 85 42,305 0.247
S484 12.06 89 4,204 0.058
S485 81.79 84 28,501 0.212
S486 41.89 87 18,248 0.274
S487 19.56 90 8,522 0.181
S488 21.95 89 9,561 0.270
S489 41.43 89 18,047 0.221
S49 42.42 85 14,782 0.331
S490 89.32 89 38,908 0.167
S491 7.93 89 3,456 0.239
S492 3.47 89 1,510 0.217
S493 21.86 90 9,523 0.189
S494 20.31 92 8,849 0.067
S495 6.08 91 2,648 0.031
S496 2.67 92 1,162 0.154
S497 10.62 92 4,625 0.297
S498 13.80 92 6,010 0.345
S499 47.08 88 16,406 0.207
S5 19.72 89 7,534 0.307
S50 28.10 84 9,792 0.264
S500 76.31 86 33,242 0.184
S501 8.14 88 1,364 0.562
S502 26.97 89 11,750 0.301
S503 20.33 81 1,771 0.164

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-11

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S504 15.99 90 6,967 0.237
S505 3.41 88 1,486 0.020
S506 9.39 90 4,091 0.178
S507 2.90 92 1,264 1.322
S508 11.10 89 4,836 0.191
S509 16.38 91 7,134 0.121
S51 5.18 89 1,803 0.145
S510 3.00 92 1,305 0.020
S511 3.10 91 1,348 0.020
S512 29.74 80 12,954 0.283
S513 7.42 82 3,231 0.062
S514 29.91 87 10,423 0.265
S515 31.95 85 11,135 0.346
S516 19.48 89 6,788 0.351
S517 59.34 85 20,680 0.253
S518 48.38 89 21,076 0.905
S519 0.87 89 473 0.769
S52 14.94 88 5,206 0.305
S520 37.30 89 12,997 0.682
S521 28.22 89 9,834 0.668
S522 58.76 90 20,477 0.320
S523 54.09 87 18,848 0.270
S524 38.82 89 13,527 0.309
S525 24.55 89 8,556 0.163
S526 51.53 87 17,957 0.247
S527 37.85 89 13,190 0.206
S528 31.50 89 10,979 0.164
S529 9.44 91 4,112 0.731
S53 62.61 88 21,819 0.259
S530 7.75 90 3,374 2.193
S531 38.79 90 16,895 0.510
S532 32.70 85 11,394 0.281
S533 127.49 83 44,428 0.217
S534 5.10 89 1,776 0.020
S535 34.60 87 12,056 0.221
S536 38.23 85 13,323 0.213
S537 3.98 87 1,387 0.081
S538 26.15 82 9,112 0.340
S539 4.58 86 1,596 1.078
S54 4.60 89 1,601 0.175
S540 32.37 86 11,280 0.196

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-12

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S541 26.81 88 9,342 0.240
S542 22.56 88 7,861 0.545
S543 6.70 85 2,336 1.534
S544 10.70 88 4,662 3.439
S545 85.28 89 29,719 0.247
S546 3.22 89 1,123 0.020
S547 58.93 89 20,536 0.227
S548 25.03 89 8,724 0.331
S549 21.98 90 7,660 0.231
S55 13.24 89 4,613 0.227
S550 31.39 88 10,938 0.260
S551 8.87 85 3,091 0.252
S552 85.27 88 29,716 0.233
S553 45.06 90 15,702 0.281
S554 29.70 89 12,935 0.250
S555 55.50 89 19,341 0.389
S556 78.99 90 34,407 0.368
S557 20.10 84 8,756 0.375
S558 7.83 89 6,825 1.525
S559 2.54 90 2,214 2.051
S56 14.14 89 4,926 0.214
S560 27.69 86 12,063 0.653
S561 11.28 91 4,911 2.206
S562 7.29 91 3,174 1.089
S563 7.46 88 2,598 0.382
S564 1.15 80 400 0.368
S565 3.67 88 3,197 0.217
S566 44.68 87 15,570 0.343
S567 39.68 88 13,828 0.430
S568 1.47 83 2,131 0.421
S569 4.01 89 1,397 0.020
S57 89.00 89 31,013 0.240
S570 26.10 83 9,094 0.399
S571 12.80 88 1,115 1.109
S572 4.49 88 1,566 1.478
S573 10.20 74 1,367 1.538
S574 26.59 87 9,265 0.301
S575 8.26 89 2,877 0.151
S576 22.21 88 7,740 0.432
S577 1.02 88 357 0.154
S578 2.42 89 843 0.093

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-13

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S579 2.92 89 1,272 0.293
S58 41.71 89 14,535 0.263
S580 13.40 86 4,668 0.265
S581 17.63 81 38,390 0.313
S582 8.39 88 18,274 0.020
S583 7.35 88 16,015 0.486
S584 10.98 86 23,908 0.020
S585 1.40 88 3,041 0.020
S586 33.48 86 8,333 0.298
S587 1.82 84 3,953 0.499
S588 2.11 88 4,593 0.554
S589 20.45 88 44,533 0.591
S59 48.71 89 16,973 0.260
S590 67.92 89 5,917 0.402
S591 41.87 87 4,053 0.185
S592 22.01 83 2,397 4.180
S593 25.09 79 2,186 0.320
S594 18.86 63 1,643 0.210
S595 34.88 86 3,575 0.755
S596 2.92 80 2,544 0.697
S597 24.76 88 5,394 0.451
S598 2.68 89 935 0.187
S599 21.02 86 2,289 0.134
S6 22.13 88 8,168 0.298
S60 9.34 89 3,255 0.179
S600 17.66 88 3,847 0.081
S601 9.30 89 3,239 0.020
S602 1.68 89 3,648 0.020
S603 10.06 82 1,947 0.318
S604 16.92 88 36,851 0.367
S605 1.71 89 3,731 0.020
S606 8.03 84 17,496 0.020
S607 73.47 92 32,005 0.531
S608 27.74 83 12,083 0.606
S609 12.86 90 28,010 0.465
S61 11.44 89 3,985 0.349
S610 4.28 84 9,323 0.450
S611 31.58 89 4,744 0.324
S612 3.86 86 1,344 0.474
S613 21.52 88 7,498 0.244
S614 2.60 87 905 0.876

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-14

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S615 1.71 89 596 0.243
S616 12.25 88 1,334 0.220
S617 4.36 89 9,486 0.264
S618 1.08 72 1,880 0.020
S619 26.95 89 11,741 0.378
S62 10.64 89 3,708 0.350
S620 2.43 90 5,283 0.020
S621 0.51 85 890 0.020
S622 0.26 89 454 0.020
S623 68.93 86 24,020 0.414
S624 64.96 88 18,863 0.212
S625 9.50 90 20,694 0.234
S626 10.55 90 22,983 0.312
S627 6.08 91 13,241 0.131
S628 24.84 86 10,820 0.438
S629 37.07 89 3,230 0.130
S63 16.12 89 5,617 0.251
S630 4.03 88 1,406 0.211
S631 41.18 85 5,979 0.294
S632 2.59 64 4,515 0.020
S633 2.39 85 5,194 0.020
S634 64.51 82 22,480 0.367
S635 12.64 63 7,866 0.391
S636 31.16 89 10,859 0.020
S637 16.68 89 5,811 0.020
S638 33.12 94 36,071 0.020
S639 34.46 92 37,528 0.020
S64 49.38 89 17,209 0.167
S640 32.72 74 35,636 0.020
S641 34.44 77 37,508 0.020
S642 241.18 68 21,012 0.262
S643 41.10 86 17,901 0.308
S644 18.82 89 6,558 0.313
S645 13.86 82 4,830 0.659
S646 26.99 89 2,351 0.045
S647 69.01 88 24,050 0.240
S648 130.18 60 11,341 0.285
S649 3.17 89 6,914 1.058
S65 13.21 89 4,602 0.208
S650 5.39 89 1,876 1.350
S651 2.04 89 711 3.585

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-15

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S652 20.29 91 8,840 0.418
S653 27.31 83 7,929 0.515
S654 21.35 89 9,300 0.326
S655 12.83 75 2,795 0.736
S656 7.28 90 3,171 0.026
S657 3.75 89 1,633 0.217
S658 1.19 83 2,590 0.020
S659 5.19 84 1,808 0.628
S66 43.47 89 15,147 0.230
S660 13.98 91 6,091 0.260
S661 24.64 87 8,587 0.248
S662 55.16 88 19,221 0.175
S663 194.12 88 67,646 0.264
S664 160.23 89 55,836 0.200
S665 39.58 86 13,793 0.345
S666 5.52 82 1,925 0.333
S667 15.47 83 5,390 0.511
S668 42.63 88 3,714 0.311
S669 13.04 89 4,544 0.595
S67 16.92 89 5,895 0.228
S670 12.80 88 4,460 0.373
S671 11.30 90 3,939 0.312
S672 27.80 83 9,687 0.332
S673 59.00 87 20,559 0.227
S674 3.11 87 6,775 0.286
S675 13.95 85 6,076 0.331
S676 73.85 92 32,171 0.234
S677 8.57 89 2,987 0.325
S678 4.02 89 1,402 0.479
S679 148.36 89 51,700 0.280
S68 6.60 90 2,298 0.177
S680 212.89 88 74,187 0.224
S681 21.07 88 1,836 0.253
S682 14.92 84 5,200 0.298
S683 10.19 88 3,552 0.020
S684 5.12 82 2,972 2.351
S685 28.07 89 6,987 0.197
S686 16.78 88 5,846 0.804
S687 1.32 88 2,875 0.020
S688 3.27 88 1,425 0.386
S689 2.64 87 1,916 2.778

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-16

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S69 5.28 89 605 0.287
S690 15.35 89 6,684 1.877
S691 10.24 88 3,570 0.377
S692 17.35 89 6,046 0.307
S693 5.15 89 1,793 0.430
S694 9.67 89 3,371 0.349
S695 3.61 89 1,258 0.300
S696 15.26 81 3,324 0.421
S697 11.68 82 4,069 0.346
S698 12.67 87 4,417 0.324
S699 8.39 84 2,924 0.282
S7 14.95 88 1,302 0.240
S70 20.14 90 3,508 0.216
S700 10.56 84 3,679 0.821
S701 8.98 81 3,128 0.528
S702 5.48 84 1,911 1.155
S703 124.78 73 10,871 0.394
S704 6.45 82 2,246 0.143
S705 35.70 88 12,442 0.180
S706 51.03 87 17,782 0.217
S71 22.44 89 7,820 0.163
S72 52.17 88 18,178 0.254
S73 5.87 81 1,137 0.903
S74 24.71 63 2,153 0.940
S75 43.89 86 3,823 0.277
S76 9.69 90 1,689 0.309
S77 7.88 89 3,433 0.282
S78 12.44 91 5,419 0.211
S79 36.48 86 3,178 0.207
S8 72.33 86 21,881 0.211
S80 22.39 89 9,755 0.589
S81 5.80 91 2,528 0.304
S82 3.71 91 1,615 0.281
S83 13.93 88 6,069 0.510
S84 4.57 81 1,990 0.326
S85 80.61 87 28,091 0.285
S86 24.46 87 8,523 0.020
S87 38.60 86 13,451 0.760
S88 4.74 79 4,132 2.209
S89 15.11 90 1,317 0.398
S9 79.08 87 20,876 0.238

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-17

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table C-1. Existing Conditions Hydrologic Parameters
S90 15.14 87 6,595 0.362
S91 20.93 87 7,294 0.220
S92 22.06 83 7,688 0.254
S93 24.13 84 8,408 0.321
S94 18.53 85 6,456 0.137
S95 7.24 85 2,523 0.302
S96 3.92 81 727 0.109
S97 45.23 85 15,763 0.325
S98 58.99 85 20,557 0.164
S99 13.98 89 4,871 0.260
SGreystone 46.06 84 8,090 0.383

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY C-18

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY

APPENDIX D FUTURE CONDITIONS HYDROLOGIC

PARAMETERS

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Lowery 52.74 80 8,660 0.395
S0 12.83 89 3,653 0.020
S1 67.59 88 22,303 0.104
S10 14.50 89 6,134 0.383
S100 8.59 82 2,994 0.221
S101 23.81 89 8,295 0.380
S102 8.91 88 3,106 0.260
S103 2.75 89 957 0.435
S104 16.56 89 5,772 0.190
S105 10.68 88 3,720 0.253
S106 5.43 89 1,893 0.051
S107 6.75 89 2,351 0.342
S108 6.91 89 2,406 0.342
S109 82.30 89 28,679 0.330
S11 161.37 87 70,294 0.261
S110 6.95 89 2,422 0.190
S111 6.22 89 2,167 0.170
S112 7.31 86 2,548 0.128
S113 19.69 87 6,860 0.426
S114 7.12 84 2,482 0.699
S115 49.27 85 17,171 0.629
S116 31.41 89 10,947 0.159
S117 100.25 89 34,936 0.248
S118 104.39 90 45,473 0.261
S119 46.19 91 20,118 0.160
S12 41.52 84 7,697 0.316
S120 18.92 91 8,242 0.270
S121 81.51 91 35,505 0.212
S122 25.29 85 8,814 0.296
S123 3.91 87 1,704 0.205
S124 17.84 85 6,216 0.255
S125 34.73 84 12,104 0.310
S126 11.51 83 4,010 0.399
S127 14.35 89 5,000 0.296
S128 15.42 88 6,718 0.229
S129 6.08 86 2,650 0.320
S13 45.58 89 18,051 0.326
S130 35.92 87 15,644 0.175
S131 1.65 84 717 0.554
S132 13.74 87 5,985 0.381
S133 12.66 84 5,513 0.582
Table D-1. Future Conditions Hydrologic Parameters

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-1

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S134 13.38 89 4,662 0.339
S135 82.03 87 28,586 0.448
S136 21.78 85 7,589 0.414
S137 11.03 84 3,844 0.318
S138 4.84 86 1,686 0.492
S139 17.78 86 6,195 0.713
S14 20.08 88 1,749 0.197
S140 10.73 84 3,740 1.048
S141 7.99 84 2,785 0.595
S142 6.87 88 2,394 0.163
S143 13.39 87 4,666 0.323
S144 1.24 89 1,805 0.181
S145 18.20 88 6,343 0.149
S146 46.41 84 16,171 0.464
S147 45.91 88 15,997 0.190
S148 14.49 89 5,051 0.193
S149 57.44 85 20,017 0.192
S15 17.81 90 7,533 0.399
S150 5.75 82 2,004 0.312
S151 6.04 83 2,104 0.335
S152 1.91 83 664 0.461
S153 18.56 82 6,466 0.260
S154 28.06 89 9,777 0.280
S155 67.89 84 23,657 0.188
S156 6.63 82 2,312 0.529
S157 5.56 84 1,937 0.185
S158 8.61 83 2,999 0.362
S159 2.64 83 920 0.402
S16 3.50 74 3,814 1.158
S160 17.28 83 6,021 0.463
S161 60.40 82 21,048 0.298
S162 24.39 83 8,499 0.352
S163 7.20 69 2,509 0.586
S164 14.25 88 4,966 0.129
S165 21.24 84 7,400 0.336
S166 25.07 88 8,737 0.293
S167 47.58 88 16,580 0.305
S168 6.20 84 2,161 0.252
S169 4.98 84 1,734 0.020
S17 19.35 86 6,433 0.849
S170 19.30 84 6,727 0.342

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-2

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S171 3.88 84 1,352 0.247
S172 22.71 90 1,979 0.084
S173 18.14 85 6,322 0.235
S174 7.01 84 2,441 0.568
S175 17.66 89 6,154 0.225
S176 13.57 89 4,728 0.181
S177 8.35 88 727 0.992
S178 40.30 84 14,044 0.243
S179 4.47 86 1,556 0.020
S18 10.82 89 4,171 0.331
S180 9.90 88 3,451 0.020
S181 2.25 82 784 0.020
S182 10.73 89 3,740 0.240
S183 22.51 89 7,845 0.026
S184 42.27 92 14,731 0.232
S185 4.24 88 1,479 0.217
S186 42.99 87 3,745 0.308
S187 38.41 83 13,385 0.284
S188 22.97 88 8,006 0.110
S189 20.61 87 7,182 0.159
S19 39.61 89 3,451 0.250
S190 43.96 84 15,319 0.259
S191 1.76 89 2,552 0.020
S192 88.12 87 30,709 0.183
S193 34.26 87 11,940 0.358
S194 24.78 83 8,634 0.559
S195 42.86 88 14,937 0.291
S196 13.51 84 4,708 0.341
S197 10.65 86 3,710 0.265
S198 18.82 86 1,639 0.226
S199 18.55 91 1,616 0.367
S2 10.75 88 4,335 0.185
S20 11.81 89 3,726 0.158
S200 8.93 81 7,776 1.548
S201 33.00 89 11,500 0.180
S202 23.26 89 3,377 0.247
S203 80.17 90 27,936 0.200
S204 38.79 82 3,380 0.378
S205 33.91 89 3,693 0.430
S206 21.15 75 1,843 0.390
S207 6.70 80 584 0.539

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-3

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S208 8.56 85 2,984 0.259
S209 64.24 88 22,386 0.263
S21 28.23 90 2,999 0.247
S210 17.07 84 5,949 0.187
S211 9.53 83 3,320 0.504
S212 37.58 88 8,185 0.326
S213 20.14 89 4,387 0.058
S214 41.29 88 14,390 0.219
S215 34.21 84 11,921 0.337
S216 23.22 82 5,058 0.355
S217 14.17 87 4,937 0.301
S218 30.43 87 10,603 0.289
S219 18.27 89 6,367 0.232
S22 2.86 88 1,038 0.317
S220 13.05 88 4,546 0.347
S221 13.69 87 1,704 0.659
S222 93.16 89 32,464 0.277
S223 4.78 89 1,664 0.516
S224 2.44 88 817 0.172
S225 3.81 92 1,659 0.492
S226 71.58 90 31,181 0.277
S227 3.40 92 1,481 0.344
S228 42.13 92 18,350 0.421
S229 8.73 84 3,042 0.209
S23 2.77 88 1,298 0.243
S230 16.78 82 5,847 0.369
S231 14.64 83 5,103 0.230
S232 13.52 84 4,711 0.306
S233 1.43 81 2,497 0.020
S234 6.99 82 2,437 0.237
S235 14.64 82 5,100 0.219
S236 7.44 81 2,593 0.115
S237 4.98 84 1,735 0.463
S238 9.15 88 3,190 0.368
S239 8.45 85 2,945 0.554
S24 7.61 88 2,351 0.285
S240 10.13 84 3,529 0.045
S241 9.38 86 817 0.374
S242 3.77 81 522 0.020
S243 19.40 77 6,761 0.771
S243b 1.41 81 490 0.771

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-4

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S244 25.52 71 2,223 0.557
S245 9.00 85 3,135 0.304
S246 9.67 82 842 0.109
S247 37.04 85 12,908 0.482
S248 127.96 86 11,148 0.514
S249 68.94 88 8,580 0.429
S25 19.87 88 7,153 0.308
S250 51.16 72 4,457 0.393
S251 67.27 82 23,442 0.914
S252 21.39 84 7,453 0.817
S253 31.39 89 10,939 0.403
S254 45.08 88 15,708 0.346
S255 27.58 88 9,613 0.748
S256 9.52 88 8,290 1.280
S257 7.61 88 2,650 0.355
S258 32.01 89 11,154 0.401
S259 42.35 88 14,760 0.310
S26 36.10 89 13,216 0.391
S260 7.95 88 2,772 0.388
S261 29.29 88 10,208 0.238
S262 15.82 88 5,514 0.480
S263 26.39 89 9,195 0.293
S264 11.09 88 3,865 0.224
S265 8.04 89 2,803 0.332
S266 9.41 89 3,279 0.293
S267 26.41 89 9,202 0.365
S268 12.15 89 5,292 0.502
S269 7.03 76 6,122 0.701
S27 21.34 89 8,452 0.434
S270 46.44 87 11,560 0.682
S271 21.70 90 9,454 0.542
S272 10.88 91 4,739 0.448
S273 30.43 90 13,257 0.339
S274 68.04 91 29,639 0.296
S275 31.81 83 11,086 0.368
S276 16.69 88 5,815 0.209
S277 14.14 88 2,053 0.323
S278 7.14 87 2,486 0.266
S279 14.43 81 5,030 0.303
S28 15.54 89 6,445 0.361
S280 32.22 88 11,230 0.297

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-5

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S281 2.94 84 1,025 0.020
S282 12.96 83 4,516 0.224
S283 16.71 81 5,823 0.381
S284 19.56 88 6,816 0.211
S285 15.47 81 5,391 0.377
S286 197.46 88 68,811 0.387
S287 69.17 86 24,105 0.594
S288 12.98 88 4,523 0.537
S289 11.86 91 2,066 0.136
S29 36.95 89 12,876 0.300
S290 130.82 89 45,588 0.254
S291 204.25 89 71,175 0.255
S292 190.91 89 66,528 0.263
S293 60.07 75 5,233 0.205
S294 25.67 84 8,945 0.188
S295 35.82 84 12,484 0.292
S296 1.97 84 686 0.186
S297 157.85 67 13,752 0.233
S298 24.30 84 8,468 0.229
S299 5.01 82 1,747 0.636
S3 25.33 89 8,173 0.223
S30 6.18 89 2,152 0.346
S300 16.60 83 5,785 0.743
S301 24.69 81 8,605 0.318
S302 10.93 84 4,762 1.083
S303 23.47 87 10,223 0.221
S304 36.47 85 12,708 0.230
S305 4.36 82 1,519 1.413
S306 13.30 83 4,635 0.562
S307 26.68 82 9,296 0.480
S308 39.76 85 13,856 0.345
S309 38.30 88 13,347 0.256
S31 10.11 89 3,521 0.773
S310 23.22 85 8,090 0.383
S311 50.04 86 17,438 0.317
S312 21.16 88 7,371 0.073
S313 10.17 88 3,545 0.291
S314 9.22 88 3,212 0.020
S315 4.18 88 1,455 0.020
S316 6.33 88 2,205 0.097
S317 28.33 85 9,873 0.287

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-6

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S318 73.81 88 25,721 0.417
S319 30.26 89 2,636 0.258
S32 17.05 88 1,486 1.519
S320 31.51 88 10,980 0.167
S321 18.66 88 5,420 0.288
S322 53.62 84 18,686 0.020
S323 5.48 83 1,911 0.305
S324 13.12 88 4,573 0.906
S325 11.85 89 4,131 0.179
S326 12.64 84 4,404 0.109
S327 48.42 87 16,874 0.528
S328 9.38 89 3,267 0.398
S329 23.96 89 8,349 0.276
S33 16.68 89 5,812 0.287
S330 16.04 89 5,589 0.338
S331 9.34 89 3,255 0.990
S332 4.67 88 4,065 1.486
S333 40.32 89 14,049 0.396
S334 41.19 89 14,355 0.207
S335 36.19 89 12,612 0.344
S336 14.34 88 4,998 0.020
S337 40.61 89 14,153 0.187
S338 41.69 88 14,529 0.319
S339 64.74 88 22,562 0.319
S34 4.24 89 1,476 0.374
S340 71.84 81 25,034 0.196
S341 17.31 70 7,539 2.513
S342 2.28 83 794 1.634
S343 3.68 83 1,281 0.788
S344 57.86 88 20,164 0.253
S345 18.03 87 6,281 0.384
S346 66.99 88 23,344 0.315
S347 35.62 86 12,411 0.105
S348 22.54 88 7,854 0.154
S349 11.73 88 4,087 0.020
S35 15.67 89 5,459 0.343
S350 72.50 89 25,264 0.260
S351 53.52 88 18,651 0.124
S352 105.11 88 36,629 0.251
S353 76.58 86 16,679 0.217
S354 44.09 88 15,363 0.284

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-7

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S355 4.70 89 1,638 0.143
S356 2.68 89 935 0.217
S357 8.53 88 2,974 0.181
S358 28.20 87 9,825 0.235
S359 16.10 90 5,612 0.214
S36 23.50 89 8,189 0.332
S360 8.00 89 2,787 0.429
S361 28.08 88 9,785 0.301
S362 23.63 84 8,234 0.331
S363 25.40 82 8,852 0.469
S364 39.87 86 13,892 0.497
S365 29.18 87 6,356 0.165
S366 23.57 87 8,214 0.217
S367 23.04 81 8,031 0.494
S368 24.14 84 8,411 0.196
S369 14.99 81 5,225 0.673
S37 15.92 89 5,549 0.221
S370 12.02 92 5,235 0.337
S371 11.90 90 1,037 0.020
S372 0.18 89 780 0.020
S373 13.75 88 4,793 0.314
S374 0.27 90 1,195 0.020
S375 32.36 89 11,278 0.291
S376 33.39 89 9,696 0.166
S377 22.70 90 7,910 0.648
S378 16.66 81 5,805 0.420
S379 3.67 81 3,193 0.545
S38 16.74 89 5,833 0.347
S380 72.54 84 25,277 0.334
S381 4.47 81 1,299 1.135
S382 43.42 71 6,877 0.791
S383 33.92 88 2,955 0.210
S384 8.59 81 748 0.215
S385 14.59 84 5,083 0.673
S386 30.43 84 10,605 0.272
S387 94.80 88 33,034 0.260
S388 37.40 88 13,034 0.143
S389 3.02 89 1,052 0.077
S39 33.77 88 11,768 0.296
S390 15.54 88 5,414 0.097
S391 13.76 86 5,992 0.493

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-8

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S392 5.82 85 4,222 1.202
S393 25.46 89 8,872 0.263
S394 18.12 81 1,579 0.227
S395 51.09 66 4,451 1.664
S396 45.87 84 8,660 0.395
S397 39.09 85 13,621 0.225
S398 67.40 88 23,487 0.329
S399 10.36 88 9,025 1.238
S4 12.08 89 4,209 0.141
S40 42.18 86 14,700 0.271
S400 62.50 88 21,780 0.249
S401 112.38 88 39,163 0.259
S402 16.91 92 14,732 0.354
S403 35.02 88 12,203 0.296
S404 1.26 88 1,098 0.461
S405 1.51 83 1,318 0.020
S406 1.87 89 1,630 0.020
S407 2.79 89 973 0.020
S408 9.36 84 3,262 0.661
S409 4.54 88 1,318 0.020
S41 23.86 88 8,314 0.315
S410 6.22 74 27,112 0.556
S411 64.04 88 27,897 0.355
S412 42.13 89 14,681 0.387
S413 17.01 89 5,927 0.409
S414 8.40 89 2,925 0.372
S415 4.74 89 1,653 0.212
S416 27.71 81 2,414 0.191
S417 35.40 81 3,084 0.168
S418 40.17 81 3,500 0.194
S419 16.72 81 2,914 0.325
S42 5.67 87 1,976 0.256
S420 99.33 82 8,653 0.572
S421 29.33 84 2,555 0.075
S422 4.15 88 3,616 0.020
S423 21.04 84 1,833 0.329
S424 17.85 88 7,773 0.322
S425 28.37 82 9,885 0.506
S426 18.81 82 6,555 0.302
S427 8.79 81 851 1.707
S428 13.90 85 1,211 0.513

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-9

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S429 68.81 85 23,979 0.184
S43 7.19 79 3,197 0.989
S430 27.75 87 9,670 0.214
S431 16.45 81 2,866 0.415
S432 17.15 89 5,978 0.438
S433 64.35 88 22,425 0.224
S434 11.18 86 3,895 0.161
S435 6.84 88 2,385 0.038
S436 77.71 88 27,081 0.251
S437 5.67 89 1,977 0.286
S438 13.73 88 4,783 0.145
S439 55.95 84 9,749 0.118
S44 4.52 87 1,575 0.387
S440 19.96 86 6,955 0.314
S441 19.31 88 6,730 0.247
S442 37.58 88 13,094 0.310
S443 5.80 89 2,022 0.163
S444 41.74 88 14,547 0.313
S445 57.39 87 20,000 0.342
S446 15.27 87 5,322 0.452
S447 21.23 90 9,248 0.240
S448 29.37 91 12,795 0.606
S449 19.48 90 8,484 0.306
S45 75.63 88 26,356 0.276
S450 4.45 91 1,938 0.374
S451 14.06 91 6,123 0.330
S452 14.34 92 6,247 0.199
S453 20.04 92 8,727 0.425
S454 38.93 92 16,959 0.998
S455 25.87 91 11,268 1.064
S456 4.46 88 1,555 0.400
S457 77.11 89 26,870 0.239
S458 9.19 92 4,002 0.150
S459 10.60 84 9,235 1.476
S46 35.60 83 12,407 0.308
S460 32.49 87 11,323 0.889
S461 19.22 88 6,698 0.355
S462 20.78 87 7,240 0.403
S463 38.39 89 3,344 0.456
S464 48.44 88 4,220 0.273
S465 27.40 91 11,936 0.332

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-10

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S466 9.37 81 3,264 0.130
S467 35.47 81 12,361 0.393
S468 7.04 84 2,452 0.327
S469 9.06 84 3,158 0.340
S47 15.15 88 5,279 0.507
S470 26.01 83 9,062 0.441
S471 36.40 84 12,686 0.307
S472 22.84 92 9,948 0.541
S473 18.77 91 8,176 0.807
S474 4.69 89 2,042 0.481
S475 5.96 86 519 0.273
S476 13.97 82 4,867 0.242
S477 26.15 84 9,114 0.465
S478 32.83 83 7,150 0.401
S479 5.43 89 2,363 0.215
S48 13.26 88 3,208 0.218
S480 103.79 87 36,169 0.256
S481 12.60 89 4,389 0.773
S482 34.96 89 12,183 0.377
S483 121.40 90 42,305 0.247
S484 12.06 89 4,204 0.058
S485 81.79 84 28,501 0.212
S486 41.89 88 18,248 0.274
S487 19.56 90 8,522 0.181
S488 21.95 89 9,561 0.270
S489 41.43 89 18,047 0.221
S49 42.42 90 14,782 0.331
S490 89.32 89 38,908 0.167
S491 7.93 89 3,456 0.239
S492 3.47 92 1,510 0.217
S493 21.86 91 9,523 0.189
S494 20.31 92 8,849 0.067
S495 6.08 92 2,648 0.031
S496 2.67 92 1,162 0.154
S497 10.62 92 4,625 0.297
S498 13.80 92 6,010 0.345
S499 47.08 89 16,406 0.207
S5 19.72 89 7,534 0.307
S50 28.10 88 9,792 0.264
S500 76.31 90 33,242 0.184
S501 8.14 88 1,364 0.562

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-11

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S502 26.97 92 11,750 0.301
S503 15.28 92 5,325 0.147
S504 15.99 92 6,967 0.237
S505 3.41 92 1,486 0.020
S506 9.39 92 4,091 0.178
S507 2.90 92 1,264 1.322
S508 11.10 92 4,836 0.191
S509 16.38 91 7,134 0.121
S51 5.18 89 1,803 0.145
S510 3.00 92 1,305 0.020
S511 3.10 92 1,348 0.020
S512 29.74 92 12,954 0.283
S513 7.42 91 3,231 0.062
S514 29.91 87 10,423 0.265
S515 31.95 87 11,135 0.346
S516 19.48 89 6,788 0.351
S517 59.34 89 20,680 0.253
S518 48.38 89 21,076 0.905
S519 0.87 89 473 0.769
S52 14.94 88 5,206 0.305
S520 37.30 89 12,997 0.682
S521 28.22 89 9,834 0.668
S522 58.76 90 20,477 0.320
S523 54.09 89 18,848 0.270
S524 38.82 89 13,527 0.309
S525 24.55 89 8,556 0.163
S526 51.53 90 17,957 0.247
S527 37.85 89 13,190 0.206
S528 31.50 89 10,979 0.164
S529 9.44 92 4,112 0.731
S53 62.61 91 21,819 0.259
S530 7.75 91 3,374 2.193
S531 38.79 91 16,895 0.510
S532 32.70 85 11,394 0.281
S533 57.93 83 20,189 0.135
S534 5.10 89 1,776 0.020
S535 34.60 88 12,056 0.221
S536 38.23 85 13,323 0.213
S537 3.98 87 1,387 0.081
S538 26.15 85 9,112 0.340
S539 4.58 86 1,596 1.078

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-12

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S54 4.60 89 1,601 0.175
S540 32.37 86 11,280 0.196
S541 26.81 88 9,342 0.240
S542 22.56 88 7,861 0.545
S543 6.70 85 2,336 1.534
S544 10.70 89 4,662 3.439
S545 85.28 89 29,719 0.247
S546 3.22 89 1,123 0.020
S547 58.93 89 20,536 0.227
S548 25.03 89 8,724 0.331
S549 21.98 90 7,660 0.231
S55 13.24 89 4,613 0.227
S550 31.39 88 10,938 0.260
S551 8.87 85 3,091 0.252
S552 85.27 88 29,716 0.233
S553 45.06 90 15,702 0.281
S554 29.70 89 12,935 0.250
S555 55.50 90 19,341 0.389
S556 78.99 90 34,407 0.368
S557 20.10 89 8,756 0.375
S558 7.83 89 6,825 1.525
S559 2.54 90 2,214 2.051
S56 14.14 89 4,926 0.214
S560 27.69 86 12,063 0.653
S561 11.28 91 4,911 2.206
S562 7.29 91 3,174 1.089
S563 7.46 88 2,598 0.382
S564 1.15 80 400 0.368
S565 3.67 88 3,197 0.217
S566 44.68 87 15,570 0.343
S567 39.68 88 13,828 0.430
S568 1.47 83 2,131 0.421
S569 4.01 89 1,397 0.020
S57 89.00 89 31,013 0.240
S570 26.10 87 9,094 0.399
S571 12.80 88 1,115 1.109
S572 4.49 88 1,566 1.478
S573 10.20 74 1,367 1.538
S574 26.59 87 9,265 0.301
S575 8.26 89 2,877 0.151
S576 22.21 88 7,740 0.432

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-13

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S577 1.02 88 357 0.154
S578 2.42 89 843 0.093
S579 2.92 89 1,272 0.293
S58 41.71 89 14,535 0.263
S580 13.40 86 4,668 0.265
S581 17.63 91 38,390 0.313
S582 8.39 92 18,274 0.020
S583 7.35 92 16,015 0.486
S584 10.98 91 23,908 0.020
S585 1.40 91 3,041 0.020
S586 33.48 90 8,333 0.298
S587 1.82 88 3,953 0.499
S588 2.11 88 4,593 0.554
S589 20.45 90 44,533 0.591
S59 48.71 89 16,973 0.260
S590 67.92 91 5,917 0.402
S591 41.87 89 4,053 0.185
S592 22.01 91 2,397 4.180
S593 25.09 91 2,186 0.320
S594 18.86 88 1,643 0.210
S595 34.88 91 3,575 0.755
S596 2.92 93 2,544 0.697
S597 24.76 92 5,394 0.451
S598 2.68 89 935 0.187
S599 21.02 87 2,289 0.134
S6 22.13 88 8,168 0.298
S60 9.34 89 3,255 0.179
S600 17.66 89 3,847 0.081
S601 9.30 89 3,239 0.020
S602 1.68 89 3,648 0.020
S603 10.06 88 1,947 0.318
S604 16.92 92 36,851 0.367
S605 1.71 92 3,731 0.020
S606 8.03 90 17,496 0.020
S607 73.47 93 32,005 0.531
S608 27.74 92 12,083 0.606
S609 12.86 92 28,010 0.465
S61 11.44 89 3,985 0.349
S610 4.28 93 9,323 0.450
S611 31.58 89 4,744 0.324
S612 3.86 88 1,344 0.474

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-14

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S613 21.52 89 7,498 0.244
S614 2.60 88 905 0.876
S615 1.71 89 596 0.243
S616 12.25 88 1,334 0.220
S617 4.36 89 9,486 0.264
S618 1.08 91 1,880 0.020
S619 26.95 92 11,741 0.378
S62 10.64 89 3,708 0.350
S620 2.43 92 5,283 0.020
S621 0.51 92 890 0.020
S622 0.26 92 454 0.020
S623 68.93 86 24,020 0.414
S624 20.35 88 7,091 0.110
S625 9.50 92 20,694 0.234
S626 10.55 92 22,983 0.312
S627 6.08 92 13,241 0.131
S628 24.84 92 10,820 0.438
S629 37.07 92 3,230 0.130
S63 16.12 89 5,617 0.251
S630 4.03 88 1,406 0.211
S631 22.12 85 7,708 0.100
S632 2.59 84 4,515 0.020
S633 2.39 88 5,194 0.020
S634 64.51 84 22,480 0.367
S635 12.64 63 7,866 0.391
S636 31.16 89 10,859 0.020
S637 16.68 89 5,811 0.020
S638 33.12 3 36,071 0.020
S639 34.46 3 37,528 0.020
S64 49.38 89 17,209 0.167
S640 32.72 3 35,636 0.020
S641 34.44 3 37,508 0.020
S642 123.49 71 10,758 0.262
S643 41.10 92 17,901 0.308
S644 18.82 89 6,558 0.313
S645 13.86 82 4,830 0.659
S646 26.99 89 2,351 0.045
S647 69.01 88 24,050 0.240
S648 130.18 79 11,341 0.285
S649 3.17 89 6,914 1.058
S65 13.21 89 4,602 0.208

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-15

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S650 5.39 89 1,876 1.350
S651 2.04 89 711 3.585
S652 20.29 92 8,840 0.418
S653 27.31 83 7,929 0.515
S654 21.35 89 9,300 0.326
S655 12.83 79 2,795 0.736
S656 7.28 92 3,171 0.026
S657 3.75 92 1,633 0.217
S658 1.19 83 2,590 0.020
S659 5.19 84 1,808 0.628
S66 43.47 89 15,147 0.230
S660 13.98 92 6,091 0.260
S661 24.64 88 8,587 0.248
S662 55.16 89 19,221 0.175
S663 194.12 88 67,646 0.264
S664 160.23 89 55,836 0.200
S665 39.58 89 13,793 0.345
S666 5.52 82 1,925 0.333
S667 15.47 83 5,390 0.511
S668 42.63 88 3,714 0.311
S669 13.04 89 4,544 0.595
S67 16.92 89 5,895 0.228
S670 12.80 91 4,460 0.373
S671 11.30 92 3,939 0.312
S672 27.80 83 9,687 0.332
S673 59.00 87 20,559 0.227
S674 3.11 89 6,775 0.286
S675 13.95 85 6,076 0.331
S676 73.85 92 32,171 0.234
S677 8.57 89 2,987 0.325
S678 4.02 89 1,402 0.479
S679 148.36 89 51,700 0.280
S68 6.60 90 2,298 0.177
S680 212.89 88 74,187 0.224
S681 21.07 89 1,836 0.253
S682 14.92 88 5,200 0.298
S683 10.19 88 3,552 0.020
S684 5.12 88 2,972 2.351
S685 28.07 89 6,987 0.197
S686 16.78 88 5,846 0.804
S687 1.32 88 2,875 0.020

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-16

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S688 3.27 88 1,425 0.386
S689 2.64 87 1,916 2.778
S69 5.28 89 605 0.287
S690 15.35 89 6,684 1.877
S691 10.24 88 3,570 0.377
S692 17.35 89 6,046 0.307
S693 5.15 89 1,793 0.430
S694 9.67 89 3,371 0.349
S695 3.61 89 1,258 0.300
S696 15.26 83 3,324 0.421
S697 11.68 82 4,069 0.346
S698 12.67 88 4,417 0.324
S699 8.39 84 2,924 0.282
S7 14.95 89 1,302 0.240
S70 20.14 91 3,508 0.216
S700 10.56 84 3,679 0.821
S701 8.98 81 3,128 0.528
S702 5.48 84 1,911 1.155
S703 124.78 73 10,871 0.394
S704 6.45 82 2,246 0.143
S705 35.70 89 12,442 0.180
S706 51.03 88 17,782 0.217
S707 41.68 81 14,523 0.180
S708 121.91 81 42,484 0.178
S709E 54.82 86 19,104 0.210
S709W 24.31 88 8,472 0.210
S71 22.44 89 7,820 0.163
S710 108.30 84 37,739 0.245
S711 40.76 87 14,204 0.061
S712 32.35 84 11,274 0.061
S713 55.00 76 19,166 0.210
S714 57.25 82 19,951 0.604
S715 160.25 79 55,842 0.174
S716 130.67 84 45,536 0.086
S717 67.23 77 23,428 0.335
S718 39.79 68 13,867 0.382
S719 100.93 88 43,712 0.206
S719B 24.69 68 500 0.500
S72 52.17 89 18,178 0.254
S722 74.19 82 25,853 0.129
S723 65.49 81 22,823 0.269

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-17

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S724 122.83 85 42,802 0.093
S726 23.79 55 8,289 0.182
S727 7.25 82 2,526 0.100
S728 17.96 52 6,259 0.368
S729 61.94 74 21,584 0.221
S73 5.87 81 1,137 0.903
S730 136.93 55 47,717 0.324
S731 30.35 89 13,220 0.083
S731E 41.05 92 17,881 0.211
S731S 12.74 90 5,550 0.083
S731W 31.78 92 13,843 0.211
S732 23.06 86 8,035 0.076
S733 35.90 92 12,511 0.055
S734 34.62 92 12,064 0.055
S735 41.99 90 14,631 0.233
S736 15.58 87 5,430 0.313
S737 26.50 83 9,235 0.513
S738 17.14 81 5,973 0.566
S739 36.45 74 12,700 0.357
S74 24.71 84 2,153 0.940
S740 38.21 61 13,315 0.312
S741 36.82 66 12,832 0.355
S742 25.11 39 8,752 0.304
S743 53.69 88 18,708 0.311
S744NE 23.11 88 8,053 0.424
S744SW 23.50 89 8,189 0.424
S745 29.02 68 10,112 0.190
S746 22.93 79 7,992 0.311
S747 20.24 89 7,053 0.056
S748 22.46 87 7,827 0.300
S749 83.74 86 29,182 0.253
S75 43.89 90 3,823 0.277
S750 7.42 68 2,585 0.100
S751 122.57 81 42,714 0.183
S753 36.80 89 12,824 0.279
S754 39.45 88 13,746 0.100
S756 12.29 68 4,282 0.100
S757 70.10 80 24,429 0.221
S758 80.07 88 27,903 0.225
S759 20.89 72 7,280 0.131
S76 9.69 92 1,689 0.309

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-18

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S760 51.06 87 17,794 0.089
S761 128.54 89 44,795 0.132
S762 80.37 75 28,230 0.070
S763 62.76 67 21,870 0.310
S764 76.73 75 26,739 0.116
S765 125.52 89 43,741 0.105
S766 79.18 89 27,593 0.256
S767 186.78 89 65,090 0.142
S768 149.03 89 51,934 0.122
S769 82.53 63 28,760 0.141
S77 7.88 92 3,433 0.282
S770 143.59 89 50,038 0.525
S771 28.33 90 9,874 0.287
S772 36.57 88 12,744 0.374
S773 56.53 79 15,526 0.394
S774 33.01 90 11,502 0.350
S775 35.24 87 12,279 0.101
S776 39.46 88 13,752 0.101
S777 39.57 88 13,789 0.196
S778 39.64 88 13,813 0.101
S779 13.39 68 4,665 0.225
S78 12.44 92 5,419 0.211
S780 30.38 68 10,588 0.378
S781 5.52 68 1,922 0.100
S782 99.16 84 34,556 0.195
S783 40.59 89 14,143 0.100
S784 173.53 87 64,591 0.422
S785 52.53 87 18,304 0.253
S786 60.51 84 21,086 0.180
S787 33.05 63 11,517 0.776
S788 149.59 45 52,129 0.643
S788W 132.98 31 46,341 0.643
S789 123.99 80 43,208 0.380
S79 36.48 89 3,178 0.207
S790 106.21 86 37,012 0.218
S791 44.68 82 15,570 0.127
S791B 50.63 86 17,644 0.127
S792 80.59 83 28,084 0.135
S793 22.55 83 7,858 0.380
S794 117.78 87 41,044 0.096
S795 69.62 86 24,259 0.399

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-19

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S796 167.13 86 58,240 0.186
S797 80.54 81 28,066 0.122
S798 81.45 85 28,385 0.113
S799 43.37 87 15,113 0.222
S8 72.33 88 21,881 0.211
S80 22.39 91 9,755 0.589
S800 20.78 53 7,241 0.249
S801 30.74 78 10,710 0.935
S802 107.96 76 37,623 0.311
S803 6.68 90 2,327 0.544
S804 5.44 43 1,896 0.100
S805 5.55 90 1,932 0.100
S806 5.45 86 1,898 0.168
S807 12.95 85 4,513 0.100
S808 6.74 89 2,349 0.100
S809 1.31 92 456 0.100
S81 5.80 92 2,528 0.304
S810 3.75 92 1,307 0.181
S811 7.50 74 2,615 0.448
S812 65.77 68 24,619 0.244
S813 80.24 88 27,964 0.151
S814 6.39 91 2,226 0.154
S815 5.56 88 1,938 0.100
S816 5.44 89 1,896 0.100
S817 5.68 45 1,978 0.100
S818 5.73 90 1,998 0.100
S819 6.59 92 2,297 0.422
S82 3.71 92 1,615 0.281
S820 58.88 87 20,519 0.016
S821 13.01 82 4,534 0.416
S822 19.05 83 6,639 0.285
S823 85.84 86 29,914 0.221
S824 9.67 51 3,368 0.576
S826 44.60 80 15,541 0.217
S827 48.45 78 16,884 0.292
S827W 21.07 88 7,342 0.292
S828 36.85 88 12,843 0.251
S829 5.64 68 1,965 0.224
S83 13.93 89 6,069 0.510
S830 23.03 89 8,019 0.203
S831 40.77 88 14,208 0.311

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-20

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S831B 39.43 88 13,741 0.311
S832 5.05 92 1,760 0.147
S833E 26.55 91 9,414 0.207
S833W 36.91 88 12,862 0.207
S834 74.79 84 26,064 0.278
S835 36.73 84 12,798 0.386
S836 6.11 78 2,131 0.553
S837 0.55 81 192 0.349
S838 18.50 80 6,447 0.387
S839 2.91 88 1,014 0.010
S84 4.57 89 1,990 0.326
S840 1.63 73 567 0.626
S841 2.66 88 928 0.010
S842 11.69 88 4,072 0.445
S843 6.36 82 2,217 0.010
S844 7.40 86 2,578 0.883
S845 13.54 88 4,718 0.477
S846 8.45 84 2,945 0.453
S847 15.10 81 5,261 0.198
S848 3.18 81 1,108 0.217
S849 23.77 85 8,282 0.343
S85 80.61 88 28,091 0.285
S850 12.20 81 4,250 0.176
S851 10.18 83 3,547 0.505
S852 2.42 81 844 0.572
S853 0.92 73 321 0.307
S854 4.06 80 1,415 0.300
S855 1.17 72 406 0.300
S856 2.16 79 752 0.300
S857 1.99 88 694 0.300
S858 1.03 64 2,726 0.446
S86 24.46 88 8,523 0.020
S87 38.60 88 13,451 0.760
S88 4.74 79 4,132 2.209
S89 15.11 92 1,317 0.398
S9 79.08 87 20,876 0.238
S90 15.14 92 6,595 0.362
S91 20.93 87 7,294 0.220
S92 22.06 86 7,688 0.254
S93 24.13 84 8,408 0.321
S94 18.53 85 6,456 0.137

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-21

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Subcatchment Name Area (ac) Curve Number Width (ft) Slope (%) Table D-1. Future Conditions Hydrologic Parameters
S95 7.24 85 2,523 0.302
S96 3.92 87 727 0.109
S97 45.23 85 15,763 0.325
S98 58.99 85 20,557 0.164
S99 13.98 89 4,871 0.260
S794W 43.00 85 14,985 0.096
EAutoPlaza 126.00 68 43,908 0.210
S755_1 39.13 88 13,957 0.210
S755_2 41.00 88 13,957 0.210
S752_1 40.03 78 14,379 0.151
S752_2 42.49 78 14,379 0.151
S725 71.73 88 25,000 0.170
S825 101.51 87 35,375 0.115
S721 81.21 81 28,300 0.293
S720 100.63 83 35,067 0.179
Slvanhoe152_1 6.58 88 2,293 0.500
Slvanhoe152_2 20.34 57.31 1,772 0.500
Slvanhoe152_3 11.66 83.98 4,063 0.500
Slvanhoe152_4 34.36 80.12 11,974 0.500
Slvanhoe152_5 44.01 52.25 15,337 0.500

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY D-22

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO

CITY OF VISALIA

MASTER PLANS AND FINANCIAL NEXUS STUDY
APPENDIX E EXISTING CONDITIONS – MODEL

JUNCTIONS AND DIVIDERS, CONDUITS,

STORAGE AREAS, PUMPS, AND OUTFALLS

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) DIV-10 JUNCTION 318.90 5.1 100
DIV-14 JUNCTION 329.00 1.8 1,204,842
DIV-16 JUNCTION 326.93 2.0 100
DIV-34 JUNCTION 317.00 11.7 470,315
DIV-36 JUNCTION 322.00 8.0 848,400
DIV-42 JUNCTION 329.69 6.3 100
DIV-50 JUNCTION 328.80 5.2 100
DIV-54 JUNCTION 299.09 6.0 204,156
DIV-60 JUNCTION 299.09 6.0 204,156
DIV-64 JUNCTION 317.27 8.7 -
DIV-66 JUNCTION 302.90 4.7 100
JCT-100 JUNCTION 301.50 18.5 109,125
JCT-1000 JUNCTION 311.86 6.1 460,418
JCT-1002 JUNCTION 315.93 6.1 3,374,686
JCT-1004 JUNCTION 314.72 3.3 238,452
JCT-1006 JUNCTION 315.55 3.5 83,447
JCT-1008 JUNCTION 315.71 4.3 435,687
JCT-1010 JUNCTION 310.30 5.0 98,854
JCT-1012 JUNCTION 306.25 10.8 188,535
JCT-1014 JUNCTION 307.54 8.5 95,000
JCT-1016 JUNCTION 304.48 11.5 73,412
JCT-1018 JUNCTION 308.48 10.2 146,012
JCT-102 JUNCTION 302.74 17.3 207,106
JCT-1020 JUNCTION 310.00 10.0 872,792
JCT-1022 JUNCTION 313.70 6.3 72,273
JCT-1024 JUNCTION 314.01 8.0 71,989
JCT-1026 JUNCTION 314.30 7.7 64,792
JCT-1028 JUNCTION 314.55 7.5 184,609
JCT-1030 JUNCTION 315.03 7.0 119,390
JCT-1032 JUNCTION 315.42 6.6 37,886
JCT-1034 JUNCTION 315.69 6.3 260,880
JCT-1036 JUNCTION 316.02 6.0 93,027
JCT-1038 JUNCTION 316.86 5.1 2,067,412
JCT-104 JUNCTION 302.94 15.1 66,174
JCT-1040 JUNCTION 312.89 9.1 410,055
JCT-1044 JUNCTION 314.05 8.0 73,728
JCT-1046 JUNCTION 314.47 8.5 58,868
JCT-1048 JUNCTION 314.72 9.3 85,959
JCT-1050 JUNCTION 315.35 8.7 27,826
Table E-1. Existing Conditions Model Junctions and Dividers

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-1

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-1052 JUNCTION 307.28 12.4 406,982
JCT-1054 JUNCTION 306.68 12.6 352,358
JCT-1056 JUNCTION 306.58 12.7 127,333
JCT-1058 JUNCTION 317.61 6.4 479,027
JCT-106 JUNCTION 304.53 13.5 878,708
JCT-1060 JUNCTION 316.42 7.6 81,922
JCT-1062 JUNCTION 303.43 6.5 100
JCT-1064 JUNCTION 298.43 10.3 164,358
JCT-1066 JUNCTION 298.86 9.8 624,482
JCT-1068 JUNCTION 299.30 9.4 203,171
JCT-1070 JUNCTION 299.77 9.2 528,184
JCT-1072 JUNCTION 300.64 7.6 1,014,352
JCT-1076 JUNCTION 302.04 8.2 422,527
JCT-1078 JUNCTION 302.50 9.5 93,174
JCT-108 JUNCTION 306.00 14.0 69,635
JCT-1080 JUNCTION 304.30 8.7 1,197,826
JCT-1082 JUNCTION 303.15 8.5 100
JCT-1084 JUNCTION 303.50 7.2 68,506
JCT-1086 JUNCTION 304.53 7.5 52,579
JCT-1088 JUNCTION 305.18 6.8 164,540
JCT-1090 JUNCTION 304.35 9.0 602,170
JCT-1092 JUNCTION 304.67 9.4 100
JCT-1094 JUNCTION 305.54 7.2 129,870
JCT-1096 JUNCTION 305.67 7.8 164,346
JCT-1098 JUNCTION 306.00 8.5 813,097
JCT-110 JUNCTION 307.00 13.0 687,289
JCT-1100 JUNCTION 306.99 9.0 505,634
JCT-1102 JUNCTION 307.50 8.5 292,317
JCT-1104 JUNCTION 307.26 13.7 100
JCT-1106 JUNCTION 307.57 12.4 537,510
JCT-1108 JUNCTION 308.12 11.9 100
JCT-1110 JUNCTION 309.99 10.0 222,428
JCT-1112 JUNCTION 311.36 6.6 273,357
JCT-1114 JUNCTION 308.96 13.0 450,003
JCT-1116 JUNCTION 308.91 13.1 39,364
JCT-1118 JUNCTION 309.87 12.1 100
JCT-1120 JUNCTION 309.75 12.3 287,818
JCT-1122 JUNCTION 310.35 11.7 14,182
JCT-1124 JUNCTION 311.46 12.5 14,568

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-2

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-1126 JUNCTION 305.19 14.8 100
JCT-1128 JUNCTION 306.55 13.5 561,737
JCT-1130 JUNCTION 309.53 10.5 250,005
JCT-1132 JUNCTION 309.02 11.0 72,386
JCT-1134 JUNCTION 308.09 7.9 100
JCT-1138 JUNCTION 308.93 6.1 100
JCT-1140 JUNCTION 309.11 4.9 100
JCT-1142 JUNCTION 309.88 4.1 100
JCT-1144 JUNCTION 310.68 3.3 100
JCT-1146 JUNCTION 310.34 3.7 100
JCT-1150 JUNCTION 310.90 3.1 291,227
JCT-1154 JUNCTION 317.49 8.5 594,933
JCT-1156 JUNCTION 313.90 12.1 100
JCT-1158 JUNCTION 312.60 13.4 100
JCT-116 JUNCTION 302.50 7.5 478,422
JCT-1160 JUNCTION 313.20 12.8 128,078
JCT-1162 JUNCTION 314.41 11.6 504,903
JCT-1170 JUNCTION 318.12 9.9 100
JCT-1172 JUNCTION 320.78 7.2 145,324
JCT-1174 JUNCTION 323.90 4.1 448,814
JCT-1176 JUNCTION 324.62 3.4 378,883
JCT-1178 JUNCTION 319.52 10.5 100
JCT-118 JUNCTION 301.00 5.0 443,666
JCT-1180 JUNCTION 318.85 11.2 100
JCT-1182 JUNCTION 317.86 12.1 858,062
JCT-1184 JUNCTION 318.54 11.5 217,272
JCT-1186 JUNCTION 319.34 12.7 119,051
JCT-1188 JUNCTION 319.52 14.5 100
JCT-1190 JUNCTION 320.50 13.5 184,121
JCT-1192 JUNCTION 325.52 8.5 82,010
JCT-1194 JUNCTION 321.10 8.9 117,187
JCT-1196 JUNCTION 322.04 10.0 204,938
JCT-1198 JUNCTION 324.50 9.5 225,098
JCT-120 JUNCTION 297.78 8.2 469,254
JCT-1200 JUNCTION 323.90 6.1 571,064
JCT-1202 JUNCTION 324.50 5.5 144,832
JCT-1204 JUNCTION 325.95 4.1 261,817
JCT-1206 JUNCTION 326.70 3.3 968,733
JCT-1208 JUNCTION 303.37 8.6 100

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-3

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-1210 JUNCTION 304.64 7.4 57,941
JCT-1214 JUNCTION 303.47 8.5 30,922
JCT-1236 JUNCTION 304.12 9.9 100
JCT-1238 JUNCTION 306.50 7.5 35,457
JCT-1240 JUNCTION 307.70 8.3 96,276
JCT-1242 JUNCTION 308.60 7.4 45,564
JCT-1244 JUNCTION 308.15 5.9 332,438
JCT-1246 JUNCTION 304.28 9.7 228,270
JCT-1248 JUNCTION 305.42 6.6 425,851
JCT-1250 JUNCTION 306.16 7.8 243,718
JCT-1252 JUNCTION 306.76 6.2 1,380,786
JCT-1254 JUNCTION 334.80 3.2 100
JCT-1256 JUNCTION 336.10 4.0 100
JCT-1258 JUNCTION 332.22 2.8 100
JCT-1260 JUNCTION 327.40 10.6 161,402
JCT-1262 JUNCTION 325.45 12.6 100
JCT-1266 JUNCTION 326.83 13.2 642,577
JCT-1268 JUNCTION 327.98 10.0 175,230
JCT-1270 JUNCTION 313.20 12.8 100
JCT-1274 JUNCTION 313.12 8.9 176,384
JCT-1278 JUNCTION 296.95 15.1 100
JCT-1280 JUNCTION 299.51 10.5 100
JCT-1282 JUNCTION 296.50 15.5 100
JCT-1284 JUNCTION 298.75 15.3 100
JCT-1286 JUNCTION 299.60 14.4 100
JCT-1288 JUNCTION 297.42 14.6 100
JCT-1290 JUNCTION 297.95 14.1 100
JCT-1292 JUNCTION 299.60 14.4 100
JCT-1296 JUNCTION 301.85 12.2 100
JCT-1298 JUNCTION 300.72 13.3 100
JCT-1302 JUNCTION 299.16 8.8 446,500
JCT-1304 JUNCTION 301.77 8.2 100
JCT-1306 JUNCTION 307.41 6.6 80,656
JCT-1308 JUNCTION 307.61 8.4 100
JCT-1310 JUNCTION 308.37 9.6 100
JCT-1312 JUNCTION 309.11 8.9 349,823
JCT-1314 JUNCTION 310.12 7.9 362,346
JCT-1316 JUNCTION 310.71 7.3 11,566
JCT-1318 JUNCTION 312.12 7.9 567,062

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-4

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-1320 JUNCTION 314.74 7.3 423,454
JCT-1322 JUNCTION 315.46 8.5 611,112
JCT-1324 JUNCTION 316.77 9.2 2,305,153
JCT-1326 JUNCTION 307.32 8.7 100
JCT-1328 JUNCTION 308.26 9.7 100
JCT-1330 JUNCTION 309.80 10.2 100
JCT-1332 JUNCTION 310.70 7.3 100
JCT-1334 JUNCTION 309.91 2.5 100
JCT-134 JUNCTION 289.07 14.9 164,241
JCT-1340 JUNCTION 309.14 10.9 100
JCT-1342 JUNCTION 308.24 10.3 298,605
JCT-1346 JUNCTION 299.83 4.2 299,109
JCT-1348 JUNCTION 301.33 2.7 188,229
JCT-1350 JUNCTION 301.62 8.4 100
JCT-136 JUNCTION 289.39 14.6 46,980
JCT-138 JUNCTION 290.12 11.9 221,251
JCT-1380 JUNCTION 306.00 4.0 298,039
JCT-1382 JUNCTION 288.38 5.6 100
JCT-1384 JUNCTION 287.33 6.7 100
JCT-1386 JUNCTION 280.79 13.2 100
JCT-1388 JUNCTION 288.60 15.4 100
JCT-1392 JUNCTION 300.07 10.1 100
JCT-1394 JUNCTION 300.00 12.0 100
JCT-1398 JUNCTION 302.26 3.9 100
JCT-140 JUNCTION 291.99 14.0 100
JCT-1400 JUNCTION 301.63 6.4 352,320
JCT-1402 JUNCTION 299.75 8.3 129,133
JCT-1404 JUNCTION 316.80 13.2 492,502
JCT-1406 JUNCTION 317.72 8.3 252,780
JCT-142 JUNCTION 292.60 11.4 146,778
JCT-144 JUNCTION 294.21 7.8 117,210
JCT-146 JUNCTION 295.20 6.8 127,229
JCT-148 JUNCTION 291.00 13.0 381,186
JCT-152 JUNCTION 297.72 12.3 437,690
JCT-154 JUNCTION 297.06 12.9 503,255
JCT-156 JUNCTION 296.26 12.0 143,268
JCT-158 JUNCTION 293.42 10.6 247,895
JCT-160 JUNCTION 291.76 12.2 100
JCT-162 JUNCTION 291.36 12.6 230,764

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-5

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-164 JUNCTION 289.90 14.1 568,962
JCT-168 JUNCTION 276.00 6.0 100
JCT-170 JUNCTION 274.00 8.0 100
JCT-172 JUNCTION 269.61 12.4 887,796
JCT-174 JUNCTION 278.68 11.3 100
JCT-176 JUNCTION 280.34 11.7 328,941
JCT-178 JUNCTION 282.32 11.7 363,191
JCT-180 JUNCTION 282.08 11.9 413,871
JCT-182 JUNCTION 283.98 16.0 783,993
JCT-196 JUNCTION 324.00 6.0 441,388
JCT-198 JUNCTION 330.70 11.6 280,619
JCT-200 JUNCTION 333.12 10.9 163,817
JCT-2001 JUNCTION 299.53 5.0 100
JCT-2002 JUNCTION 299.50 5.0 100
JCT-2003 JUNCTION 299.27 5.0 100
JCT-2004 JUNCTION 299.00 5.0 100
JCT-2005 JUNCTION 298.97 5.0 100
JCT-2010 JUNCTION 285.10 16.4 100
JCT-2011 JUNCTION 284.66 15.9 100
JCT-2012 JUNCTION 283.61 16.5 100
JCT-2014 JUNCTION 314.25 14.5 100
JCT-2015 JUNCTION 313.55 15.7 100
JCT-2016 JUNCTION 317.81 10.5 100
JCT-2017 JUNCTION 317.55 10.6 100
JCT-2018 JUNCTION 317.53 10.5 100
JCT-2019 JUNCTION 317.47 10.4 100
JCT-202 JUNCTION 332.29 9.7 272,118
JCT-2020 JUNCTION 323.87 15.9 100
JCT-2021 JUNCTION 323.47 17.5 100
JCT-2025 JUNCTION 286.38 14.2 100
JCT-2026 JUNCTION 285.83 14.7 100
JCT-2027 JUNCTION 285.63 15.2 100
JCT-2028 JUNCTION 285.42 15.7 100
JCT-2029 JUNCTION 305.68 11.3 100
JCT-2033 JUNCTION 315.93 16.5 355,661
JCT-2034 JUNCTION 315.49 16.9 100
JCT-2035 JUNCTION 315.00 16.7 816,145
JCT-2036 JUNCTION 314.16 17.1 190,819
JCT-2037 JUNCTION 308.78 8.0 65,553

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-6

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-2038 JUNCTION 304.50 13.8 283,996
JCT-2041 JUNCTION 282.24 8.8 68,464
JCT-2042 JUNCTION 282.12 8.8 68,464
JCT-2043 JUNCTION 281.97 9.3 100
JCT-2044 JUNCTION 281.86 9.4 100
JCT-2045 JUNCTION 281.67 9.3 100
JCT-2046 JUNCTION 281.24 9.0 180,462
JCT-2047 JUNCTION 280.43 9.4 180,462
JCT-2048 JUNCTION 279.60 10.2 100
JCT-2049 JUNCTION 279.21 10.8 100
JCT-2050 JUNCTION 308.04 10.3 100
JCT-2051 JUNCTION 307.50 11.1 100
JCT-2052 JUNCTION 307.05 12.1 100
JCT-2053 JUNCTION 306.70 12.0 100
JCT-2054 JUNCTION 306.36 13.0 100
JCT-2055 JUNCTION 306.21 12.7 100
JCT-2056 JUNCTION 326.75 13.7 485,729
JCT-2057 JUNCTION 326.39 14.9 100
JCT-2058 JUNCTION 326.04 14.1 100
JCT-206 JUNCTION 325.25 14.8 100
JCT-2060 JUNCTION 324.90 15.9 100
JCT-2061 JUNCTION 325.17 15.3 100
JCT-2062 JUNCTION 340.64 9.9 100
JCT-2063 JUNCTION 339.99 12.2 100
JCT-2064 JUNCTION 339.62 12.8 100
JCT-2066 JUNCTION 308.88 8.5 100
JCT-2067 JUNCTION 308.80 8.0 36,416
JCT-2068 JUNCTION 308.16 9.1 100
JCT-2069 JUNCTION 308.00 9.3 257,660
JCT-2071 JUNCTION 309.03 8.0 1,026,484
JCT-2073 JUNCTION 306.10 7.2 354,750
JCT-2074 JUNCTION 305.10 8.3 130,324
JCT-2075 JUNCTION 303.70 10.7 274,191
JCT-2076 JUNCTION 301.44 14.2 100
JCT-2077 JUNCTION 300.07 10.3 611,329
JCT-2078 JUNCTION 298.14 12.6 430,255
JCT-2079 JUNCTION 295.88 14.3 559,432
JCT-208 JUNCTION 326.50 13.5 100
JCT-2081 JUNCTION 291.62 10.6 100

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-7

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-2082 JUNCTION 291.28 10.7 100
JCT-2083 JUNCTION 289.73 12.1 100
JCT-2084 JUNCTION 289.22 14.0 100
JCT-2085 JUNCTION 295.17 13.4 100
JCT-2086 JUNCTION 296.25 13.1 100
JCT-2087 JUNCTION 296.17 10.8 100
JCT-2088 JUNCTION 281.15 4.9 283,092
JCT-2089 JUNCTION 280.58 6.0 100
JCT-2090 JUNCTION 279.99 7.0 100
JCT-2092 JUNCTION 276.19 2.5 7,554
JCT-2093 JUNCTION 275.32 11.2 100,000
JCT-2094 JUNCTION 273.65 11.9 106,152
JCT-2095 JUNCTION 274.93 11.9 100
JCT-2096 JUNCTION 305.29 11.3 100
JCT-2097 JUNCTION 333.84 9.7 67,614
JCT-2099 JUNCTION 341.49 9.1 100
JCT-210 JUNCTION 328.86 9.1 232,497
JCT-2100 JUNCTION 341.14 8.5 111,032
JCT-2101 JUNCTION 340.88 9.1 100
JCT-2102 JUNCTION 340.75 9.5 100
JCT-2103 JUNCTION 340.66 9.7 100
JCT-2104 JUNCTION 316.24 15.4 100
JCT-2105 JUNCTION 316.71 14.1 169,339
JCT-2106 JUNCTION 317.25 10.2 134,441
JCT-2108 JUNCTION 312.49 12.6 168,467
JCT-2109 JUNCTION 312.11 12.0 100
JCT-2110 JUNCTION 311.67 11.3 54,492
JCT-2111 JUNCTION 311.21 11.3 100
JCT-2112 JUNCTION 310.88 12.2 100
JCT-2113 JUNCTION 307.50 15.9 529,647
JCT-2114 JUNCTION 312.74 9.7 700,735
JCT-2115 JUNCTION 312.21 10.9 100
JCT-2116 JUNCTION 311.57 12.7 100
JCT-2117 JUNCTION 311.52 11.9 100
JCT-2118 JUNCTION 310.98 12.0 100
JCT-2119 JUNCTION 310.57 12.4 100
JCT-212 JUNCTION 330.24 7.8 85,254
JCT-2120 JUNCTION 310.34 12.4 284,244
JCT-2121 JUNCTION 309.74 12.4 100

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-8

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-2122 JUNCTION 309.47 12.7 100
JCT-2123 JUNCTION 308.91 13.4 100
JCT-2124 JUNCTION 308.28 16.0 232,650
JCT-2125 JUNCTION 307.99 17.6 100
JCT-2126 JUNCTION 302.36 10.0 140,738
JCT-2127 JUNCTION 301.48 10.2 119,539
JCT-2128 JUNCTION 300.69 11.7 62,462
JCT-2129 JUNCTION 299.92 12.3 100
JCT-2130 JUNCTION 299.67 12.3 27,452
JCT-2131 JUNCTION 299.03 13.5 100
JCT-2132 JUNCTION 298.50 15.6 89,604
JCT-2134 JUNCTION 302.08 9.7 125,648
JCT-2135 JUNCTION 301.72 9.8 125,648
JCT-2136 JUNCTION 301.36 9.3 125,647
JCT-2137 JUNCTION 301.23 9.4 125,647
JCT-2138 JUNCTION 292.31 10.6 100
JCT-2139 JUNCTION 290.31 11.9 100
JCT-214 JUNCTION 326.51 13.5 100
JCT-2140 JUNCTION 287.29 15.9 100
JCT-2141 JUNCTION 297.02 7.6 380,656
JCT-2142 JUNCTION 296.47 7.7 20,788
JCT-2143 JUNCTION 296.29 7.5 100
JCT-2144 JUNCTION 295.79 7.4 100
JCT-2145 JUNCTION 294.91 8.1 100
JCT-2146 JUNCTION 293.51 8.7 324,475
JCT-2147 JUNCTION 294.84 7.2 641,152
JCT-2148 JUNCTION 294.53 7.5 45,635
JCT-2149 JUNCTION 294.20 9.0 100
JCT-2150 JUNCTION 293.88 9.9 121,995
JCT-2151 JUNCTION 293.57 9.3 110,182
JCT-2152 JUNCTION 293.14 8.5 95,467
JCT-2154 JUNCTION 303.75 7.3 301,088
JCT-2156 JUNCTION 309.52 8.1 755,909
JCT-2157 JUNCTION 304.67 11.0 100
JCT-2158 JUNCTION 303.82 11.4 100
JCT-2159 JUNCTION 303.67 11.7 100
JCT-216 JUNCTION 326.80 11.2 226,567
JCT-2160 JUNCTION 302.90 12.6 100
JCT-2161 JUNCTION 271.60 14.0 100

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-9

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-2162 JUNCTION 284.86 15.7 100
JCT-2163 JUNCTION 317.03 14.4 100
JCT-2168 JUNCTION 329.18 5.8 100
JCT-2169 JUNCTION 283.13 17.1 100
JCT-2170 JUNCTION 282.90 18.6 100
JCT-2171 JUNCTION 282.81 18.1 100
JCT-2172 JUNCTION 282.46 19.0 100
JCT-2174 JUNCTION 320.57 10.9 258,591
JCT-2175 JUNCTION 320.18 12.9 675,015
JCT-2176 JUNCTION 319.86 14.0 100
JCT-2177 JUNCTION 319.59 12.6 100
JCT-2178 JUNCTION 319.55 14.7 100
JCT-2179 JUNCTION 319.29 12.5 100
JCT-218 JUNCTION 327.10 10.9 175,945
JCT-2180 JUNCTION 319.09 12.4 29,584
JCT-2181 JUNCTION 318.67 13.7 161,093
JCT-2182 JUNCTION 318.40 14.3 17,096
JCT-2183 JUNCTION 318.37 14.2 395,557
JCT-2184 JUNCTION 317.99 14.5 22,421
JCT-2185 JUNCTION 317.68 14.8 100
JCT-2186 JUNCTION 317.39 14.8 100
JCT-2189 JUNCTION 324.00 1.3 100
JCT-2190 JUNCTION 326.50 1.3 100
JCT-2191 JUNCTION 322.50 1.3 -
JCT-2192 JUNCTION 325.50 1.3 -
JCT-2193 JUNCTION 325.50 1.3 -
JCT-2194 JUNCTION 328.00 1.3 -
JCT-2195 JUNCTION 325.50 6.5 10
JCT-2196 JUNCTION 324.00 10.2 100
JCT-2198 JUNCTION 288.22 16.3 100
JCT-2199 JUNCTION 288.83 15.7 100
JCT-22 JUNCTION 318.77 10.1 947,383
JCT-220 JUNCTION 327.98 10.0 100
JCT-2200 JUNCTION 292.65 14.1 100
JCT-2201 JUNCTION 285.50 16.5 100
JCT-2202 JUNCTION 287.05 14.6 100
JCT-2203 JUNCTION 294.57 9.3 100
JCT-2204 JUNCTION 293.20 11.7 204,720
JCT-2205 JUNCTION 292.70 11.9 100

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-10

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-2206 JUNCTION 291.73 13.5 100
JCT-2207 JUNCTION 296.22 10.0 100
JCT-2208 JUNCTION 292.92 12.3 100
JCT-2209 JUNCTION 293.04 11.8 65,270
JCT-2210 JUNCTION 296.98 7.8 24,647
JCT-2211 JUNCTION 288.60 10.4 600
JCT-2212 JUNCTION 329.00 4.6 100
JCT-2213 JUNCTION 328.00 5.7 100
JCT-2214 JUNCTION 323.61 10.0 100
JCT-2215 JUNCTION 323.46 9.3 100
JCT-2216 JUNCTION 332.18 7.1 100
JCT-2217 JUNCTION 323.00 16.9 100
JCT-2218 JUNCTION 298.24 5.0 100
JCT-2219 JUNCTION 308.95 9.1 100
JCT-222 JUNCTION 330.10 5.9 309,741
JCT-2221 JUNCTION 307.26 15.6 100
JCT-2222 JUNCTION 306.82 14.2 100
JCT-2223 JUNCTION 306.44 14.0 100
JCT-2224 JUNCTION 306.07 13.7 100
JCT-2225 JUNCTION 305.70 14.6 100
JCT-2226 JUNCTION 305.25 14.0 514,142
JCT-2227 JUNCTION 304.83 15.3 100
JCT-2228 JUNCTION 300.00 0.7 -
JCT-2229 JUNCTION 301.00 0.7 -
JCT-2230 JUNCTION 305.75 0.7 -
JCT-2231 JUNCTION 319.94 9.2 43,415
JCT-2233 JUNCTION 319.44 9.1 100
JCT-2234 JUNCTION 317.82 9.5 100
JCT-2235 JUNCTION 297.42 8.2 100
JCT-2236 JUNCTION 285.87 12.3 381,540
JCT-2237 JUNCTION 282.74 15.1 100
JCT-2239 JUNCTION 280.49 23.5 100
JCT-224 JUNCTION 328.80 7.2 309,741
JCT-2240 JUNCTION 306.25 5.0 100
JCT-2241 JUNCTION 342.36 7.6 129,839
JCT-2243 JUNCTION 345.00 0.5 100
JCT-2244 JUNCTION 344.97 0.5 100
JCT-2245 JUNCTION 344.53 0.5 -
JCT-2246 JUNCTION 344.50 0.5 -

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-11

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-2247 JUNCTION 344.00 4.2 100
JCT-2248 JUNCTION 340.06 3.6 100
JCT-2251 JUNCTION 316.29 12.7 100
JCT-2252 JUNCTION 315.71 12.7 100
JCT-2254 JUNCTION 315.60 12.4 100
JCT-2255 JUNCTION 321.01 7.0 100
JCT-2256 JUNCTION 317.61 12.0 100
JCT-2257 JUNCTION 325.47 4.5 133,741
JCT-2258 JUNCTION 318.00 11.4 1,242,344
JCT-2259 JUNCTION 317.23 12.7 100
JCT-2261 JUNCTION 330.69 5.3 100
JCT-2262 JUNCTION 330.19 4.7 134,239
JCT-2263 JUNCTION 330.00 5.0 100
JCT-2264 JUNCTION 329.24 7.6 336,421
JCT-2265 JUNCTION 316.09 18.4 100
JCT-2267 JUNCTION 328.92 6.2 74,905
JCT-2268 JUNCTION 327.30 6.4 149,543
JCT-2269 JUNCTION 326.82 7.2 100
JCT-2270 JUNCTION 326.24 7.8 130,531
JCT-2271 JUNCTION 325.26 7.9 100
JCT-2272 JUNCTION 329.44 5.6 254,493
JCT-2273 JUNCTION 328.46 7.1 96,594
JCT-2274 JUNCTION 333.70 4.0 100
JCT-2275 JUNCTION 276.63 13.3 100
JCT-2276 JUNCTION 277.98 11.2 100
JCT-2277 JUNCTION 279.37 9.8 501,432
JCT-228 JUNCTION 329.37 4.6 100
JCT-2280 JUNCTION 326.50 1.3 100
JCT-2281 JUNCTION 325.00 1.3 100
JCT-2282 JUNCTION 300.38 9.6 100
JCT-2283 JUNCTION 324.00 1.3 -
JCT-2284 JUNCTION 323.68 7.8 100
JCT-2285 JUNCTION 324.55 6.5 134,562
JCT-2286 JUNCTION 325.02 5.0 121,442
JCT-2287 JUNCTION 318.56 10.7 100
JCT-2288 JUNCTION 322.64 12.0 100
JCT-2289 JUNCTION 321.47 14.3 64,500
JCT-2290 JUNCTION 320.94 14.1 100
JCT-2291 JUNCTION 323.43 11.6 514,551

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-12

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-2292 JUNCTION 322.90 15.1 100
JCT-2293 JUNCTION 319.93 15.1 42,485
JCT-2294 JUNCTION 319.28 15.7 103,946
JCT-2295 JUNCTION 288.40 14.6 100
JCT-2296 JUNCTION 290.90 4.1 100
JCT-2297 JUNCTION 290.90 4.1 100
JCT-2298 JUNCTION 304.25 10.0 78,038
JCT-232 JUNCTION 334.25 5.8 287,077
JCT-234 JUNCTION 334.77 5.2 115,949
JCT-236 JUNCTION 335.33 7.0 100
JCT-238 JUNCTION 336.33 5.7 86,627
JCT-24 JUNCTION 322.00 6.0 475,894
JCT-240 JUNCTION 334.91 13.1 100
JCT-242 JUNCTION 335.25 12.8 100
JCT-244 JUNCTION 335.58 12.4 867,751
JCT-248 JUNCTION 334.00 10.0 100
JCT-250 JUNCTION 337.00 9.0 100
JCT-254 JUNCTION 334.25 7.8 100
JCT-256 JUNCTION 336.65 7.4 383,870
JCT-258 JUNCTION 338.12 5.9 84,934
JCT-26 JUNCTION 320.80 8.0 310,025
JCT-260 JUNCTION 339.00 5.0 298,652
JCT-270 JUNCTION 339.25 4.8 152,630
JCT-272 JUNCTION 338.00 4.0 119,466
JCT-274 JUNCTION 337.25 4.8 71,163
JCT-276 JUNCTION 336.80 5.2 97,712
JCT-278 JUNCTION 335.63 6.4 491,944
JCT-280 JUNCTION 333.80 6.2 194,820
JCT-284 JUNCTION 327.98 10.0 216,422
JCT-286 JUNCTION 329.00 7.0 11,950
JCT-290 JUNCTION 326.48 10.5 100
JCT-298 JUNCTION 331.10 2.9 406,725
JCT-30 JUNCTION 317.40 11.4 137,145
JCT-302 JUNCTION 332.00 5.0 100
JCT-308 JUNCTION 324.38 10.6 51,797
JCT-310 JUNCTION 324.30 11.0 70,119
JCT-312 JUNCTION 324.18 11.6 82,876
JCT-314 JUNCTION 323.82 11.8 443,359
JCT-316 JUNCTION 322.77 12.0 457,765

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-13

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-34 JUNCTION 320.00 4.0 100
JCT-346 JUNCTION 299.00 5.5 393,952
JCT-348 JUNCTION 300.61 5.0 232,603
JCT-350 JUNCTION 299.84 6.8 66,482
JCT-352 JUNCTION 299.67 7.3 29,847
JCT-354 JUNCTION 300.09 6.8 49,912
JCT-356 JUNCTION 298.81 8.8 86,670
JCT-358 JUNCTION 299.72 7.2 429,080
JCT-36 JUNCTION 329.97 16.0 100
JCT-360 JUNCTION 298.24 10.3 674,564
JCT-362 JUNCTION 297.89 12.0 100
JCT-364 JUNCTION 299.31 10.5 306,720
JCT-366 JUNCTION 297.62 13.2 100
JCT-370 JUNCTION 300.46 7.5 100
JCT-372 JUNCTION 297.59 8.4 133,562
JCT-374 JUNCTION 296.99 11.0 100
JCT-38 JUNCTION 328.99 17.0 100
JCT-382 JUNCTION 303.06 8.3 1,057,760
JCT-384 JUNCTION 301.50 9.5 295,910
JCT-388 JUNCTION 301.25 9.8 100
JCT-390 JUNCTION 300.89 7.5 287,753
JCT-392 JUNCTION 300.60 8.8 100
JCT-394 JUNCTION 302.66 12.0 1,158,469
JCT-396 JUNCTION 300.44 11.0 124,529
JCT-398 JUNCTION 301.20 11.0 48,354
JCT-40 JUNCTION 330.61 15.4 100
JCT-400 JUNCTION 303.00 9.0 278,009
JCT-406 JUNCTION 314.77 6.2 205,124
JCT-408 JUNCTION 312.42 9.6 493,193
JCT-410 JUNCTION 316.05 5.0 2,861,721
JCT-42 JUNCTION 332.00 14.0 815,868
JCT-436 JUNCTION 290.83 8.2 925,371
JCT-438 JUNCTION 291.58 7.4 448,114
JCT-44 JUNCTION 333.21 12.8 321,638
JCT-442 JUNCTION 304.80 4.1 100
JCT-446 JUNCTION 300.85 7.2 100
JCT-448 JUNCTION 300.60 9.4 100
JCT-450 JUNCTION 300.60 9.4 100
JCT-454 JUNCTION 300.17 11.3 100

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-14

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-456 JUNCTION 310.40 7.6 500,378
JCT-46 JUNCTION 335.21 9.8 368,733
JCT-460 JUNCTION 299.00 13.0 697,066
JCT-462 JUNCTION 298.19 13.8 100
JCT-464 JUNCTION 296.58 15.4 100
JCT-466 JUNCTION 297.30 16.7 100
JCT-468 JUNCTION 301.44 12.6 356,234
JCT-470 JUNCTION 299.13 14.9 240,183
JCT-472 JUNCTION 300.00 14.0 209,930
JCT-474 JUNCTION 300.44 13.6 282,146
JCT-476 JUNCTION 302.12 13.9 799,515
JCT-478 JUNCTION 320.95 7.5 100
JCT-48 JUNCTION 306.00 12.0 411,001
JCT-486 JUNCTION 318.85 5.2 100
JCT-490 JUNCTION 316.80 7.2 100
JCT-50 JUNCTION 304.26 13.7 100
JCT-516 JUNCTION 325.47 4.5 100
JCT-52 JUNCTION 298.60 19.4 53,103
JCT-54 JUNCTION 299.36 18.6 100
JCT-56 JUNCTION 299.77 18.2 714,283
JCT-58 JUNCTION 301.33 18.7 305,865
JCT-590 JUNCTION 308.00 14.0 10,000
JCT-594 JUNCTION 277.50 4.5 100
JCT-60 JUNCTION 305.63 10.0 161,563
JCT-618 JUNCTION 312.74 11.3 100
JCT-62 JUNCTION 302.76 12.0 225,765
JCT-620 JUNCTION 311.90 12.1 100
JCT-634 JUNCTION 322.19 13.0 100
JCT-64 JUNCTION 302.39 15.0 100
JCT-656 JUNCTION 327.82 11.5 563,291
JCT-658 JUNCTION 332.54 9.0 100
JCT-66 JUNCTION 298.40 19.5 100
JCT-662 JUNCTION 326.25 3.8 293,369
JCT-664 JUNCTION 326.31 3.7 100
JCT-666 JUNCTION 327.16 2.0 309,479
JCT-670 JUNCTION 321.06 7.3 10
JCT-676 JUNCTION 321.00 9.0 100
JCT-68 JUNCTION 298.90 19.0 100
JCT-682 JUNCTION 291.98 8.0 255,584

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-15

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-684 JUNCTION 291.71 8.3 276,912
JCT-686 JUNCTION 290.91 10.1 59,782
JCT-690 JUNCTION 295.97 6.0 205,427
JCT-692 JUNCTION 295.45 6.6 74,179
JCT-694 JUNCTION 294.52 7.0 71,880
JCT-696 JUNCTION 293.65 6.4 225,573
JCT-698 JUNCTION 293.29 6.7 74,348
JCT-70 JUNCTION 309.66 9.0 100
JCT-700 JUNCTION 293.12 6.9 100
JCT-702 JUNCTION 291.89 8.1 100
JCT-704 JUNCTION 293.87 6.1 455,828
JCT-706 JUNCTION 294.56 5.4 209,327
JCT-708 JUNCTION 295.51 4.5 147,367
JCT-710 JUNCTION 296.19 3.8 152,280
JCT-712 JUNCTION 296.64 3.4 36,323
JCT-718 JUNCTION 285.72 14.3 100
JCT-72 JUNCTION 310.13 8.0 353,687
JCT-720 JUNCTION 286.28 13.7 100
JCT-722 JUNCTION 287.42 12.6 445,590
JCT-724 JUNCTION 287.88 12.1 154,955
JCT-726 JUNCTION 289.50 10.5 154,955
JCT-728 JUNCTION 290.46 9.5 523,862
JCT-730 JUNCTION 292.13 15.5 43,868
JCT-738 JUNCTION 293.26 11.7 100
JCT-74 JUNCTION 306.00 12.0 121,538
JCT-740 JUNCTION 293.70 10.6 489,604
JCT-742 JUNCTION 294.18 10.3 66,321
JCT-750 JUNCTION 276.00 28.0 100
JCT-752 JUNCTION 289.36 16.4 100
JCT-76 JUNCTION 300.27 19.7 179,182
JCT-760 JUNCTION 280.50 25.5 100
JCT-762 JUNCTION 283.02 25.0 100
JCT-764 JUNCTION 284.79 21.2 197,173
JCT-766 JUNCTION 286.22 19.8 293,219
JCT-768 JUNCTION 287.25 16.8 131,082
JCT-770 JUNCTION 287.60 16.4 192,002
JCT-772 JUNCTION 284.22 23.8 100
JCT-776 JUNCTION 306.60 3.4 56,555
JCT-778 JUNCTION 299.50 6.5 130,105

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-16

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-78 JUNCTION 304.00 14.0 283,850
JCT-780 JUNCTION 300.20 5.8 468,945
JCT-782 JUNCTION 300.80 5.2 815,385
JCT-790 JUNCTION 327.11 16.9 302,349
JCT-792 JUNCTION 327.93 16.3 166,414
JCT-794 JUNCTION 329.53 14.5 388,097
JCT-796 JUNCTION 339.63 4.4 384,634
JCT-798 JUNCTION 329.97 14.0 210,617
JCT-80 JUNCTION 302.66 17.3 300,636
JCT-800 JUNCTION 331.84 10.2 311,666
JCT-802 JUNCTION 332.98 11.0 435,907
JCT-804 JUNCTION 333.59 9.4 45,320
JCT-806 JUNCTION 334.04 9.0 479,402
JCT-808 JUNCTION 330.69 13.3 180,744
JCT-810 JUNCTION 331.47 12.5 251,141
JCT-812 JUNCTION 332.11 11.9 1,213,071
JCT-814 JUNCTION 333.51 10.5 246,414
JCT-82 JUNCTION 304.14 15.9 1,009,148
JCT-820 JUNCTION 329.87 6.1 676,864
JCT-822 JUNCTION 337.96 3.6 603,939
JCT-824 JUNCTION 335.24 2.8 391,210
JCT-826 JUNCTION 336.28 2.0 271,964
JCT-828 JUNCTION 334.96 3.0 100
JCT-830 JUNCTION 331.40 6.6 472,065
JCT-832 JUNCTION 330.41 7.6 100
JCT-84 JUNCTION 312.00 12.0 100
JCT-846 JUNCTION 324.57 11.4 100
JCT-848 JUNCTION 324.88 9.1 212,602
JCT-850 JUNCTION 325.95 8.1 79,910
JCT-854 JUNCTION 327.75 6.3 28,574
JCT-856 JUNCTION 329.13 2.9 128,522
JCT-858 JUNCTION 328.30 5.7 303,923
JCT-860 JUNCTION 328.64 5.4 100
JCT-862 JUNCTION 327.58 7.4 259,090
JCT-864 JUNCTION 335.00 2.0 35,063
JCT-866 JUNCTION 331.00 3.0 218,691
JCT-868 JUNCTION 325.95 6.1 100,963
JCT-870 JUNCTION 324.24 9.8 606,166
JCT-874 JUNCTION 323.55 12.5 46,785

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-17

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-88 JUNCTION 312.32 16.2 323,978
JCT-880 JUNCTION 324.15 9.9 100
JCT-882 JUNCTION 324.00 6.0 100
JCT-884 JUNCTION 323.04 8.8 100
JCT-886 JUNCTION 323.30 8.9 100
JCT-888 JUNCTION 323.43 10.2 100
JCT-890 JUNCTION 328.67 5.5 161,094
JCT-894 JUNCTION 323.35 10.7 149,124
JCT-896 JUNCTION 323.70 10.3 181,295
JCT-898 JUNCTION 325.25 8.8 177,455
JCT-900 JUNCTION 326.80 7.2 199,152
JCT-902 JUNCTION 326.05 10.0 270,399
JCT-910 JUNCTION 290.90 4.1 100
JCT-912 JUNCTION 291.99 14.0 100
JCT-914 JUNCTION 291.84 13.3 100
JCT-916 JUNCTION 299.04 4.4 72,284
JCT-918 JUNCTION 291.71 10.0 194,056
JCT-920 JUNCTION 294.78 10.6 100
JCT-922 JUNCTION 295.59 9.1 100
JCT-924 JUNCTION 296.03 9.6 82,055
JCT-926 JUNCTION 297.27 8.0 29,477
JCT-928 JUNCTION 297.51 7.0 233,491
JCT-930 JUNCTION 288.40 6.6 100
JCT-932 JUNCTION 301.50 6.5 100
JCT-934 JUNCTION 302.40 5.6 824,229
JCT-936 JUNCTION 304.40 3.6 100
JCT-938 JUNCTION 302.45 2.5 100,732
JCT-940 JUNCTION 301.40 3.5 100
JCT-942 JUNCTION 298.69 5.2 507,409
JCT-944 JUNCTION 298.02 8.0 76,486
JCT-946 JUNCTION 293.54 12.5 340,049
JCT-948 JUNCTION 294.17 10.8 133,051
JCT-950 JUNCTION 295.98 8.0 82,025
JCT-952 JUNCTION 296.90 7.1 319,320
JCT-954 JUNCTION 297.80 6.2 573,373
JCT-956 JUNCTION 296.71 7.3 116,352
JCT-958 JUNCTION 295.42 10.6 41,567
JCT-96 JUNCTION 308.00 12.0 417,522
JCT-960 JUNCTION 296.33 9.7 934,728

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-18

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Junction Name Type Invert Elevation (ft) Maximum Depth (ft) Ponded Area (sq ft) Table E-1. Existing Conditions Model Junctions and Dividers JCT-964 JUNCTION 299.67 8.3 377,746
JCT-968 JUNCTION 303.32 5.5 234,401
JCT-970 JUNCTION 303.25 5.8 30,981
JCT-972 JUNCTION 301.25 5.4 100
JCT-974 JUNCTION 301.70 5.4 100
JCT-976 JUNCTION 282.93 21.1 100
JCT-978 JUNCTION 285.78 16.2 248,714
JCT-98 JUNCTION 306.98 13.0 337,009
JCT-980 JUNCTION 291.73 12.3 814,361
JCT-982 JUNCTION 287.40 14.6 148,189
JCT-984 JUNCTION 287.40 14.6 100
JCT-986 JUNCTION 288.30 13.7 449,907
JCT-988 JUNCTION 302.02 4.2 100
JCT-990 JUNCTION 302.66 11.3 101,180
JCT-992 JUNCTION 304.09 9.9 266,765
JCT-994 JUNCTION 306.72 11.3 210,059
JCT-996 JUNCTION 308.65 9.4 361,792
JCT-998 JUNCTION 310.00 8.0 337,892
JCT-BEECH JUNCTION 309.00 10.0 100
JCT-E1 JUNCTION 303.50 5.7 1,267,765
JCT-MG JUNCTION 320.87 5.2 882,221
JCT-MK JUNCTION 286.00 6.0 150,081
JEG-02 JUNCTION 323.80 11.3 38,717
JEG-03 JUNCTION 322.00 11.9 100,745
JG-1 JUNCTION 315.00 9.0 1,021,200
JG-10 JUNCTION 313.73 12.3 536,975
JG-11 JUNCTION 307.89 12.6 583,342
JG-13 JUNCTION 299.82 12.7 1,912,668
JG-14 JUNCTION 295.47 14.5 744,627
JG-16 JUNCTION 302.50 7.5 88,145
JG-17 JUNCTION 299.09 9.1 175,693
JG-2 JUNCTION 310.15 13.9 547,959
JG-ShirkW JUNCTION 281.75 18.1 100
JO-440 JUNCTION 287.00 13.0 100
JCT-GD1 JUNCTION 254.00 29.0 100
JCTN-27 JUNCTION 297.48 11.0 100.00 DIV-12 DIVIDER 316.76 1.0 - DIV-52 DIVIDER 328.01 5.7 -

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-19

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Conduit Name Type U/S Invert Elevation (ft) D/S Invert Elevation (ft) Length (ft) Diameter (ft) 5 CIRCULAR 303.50 297.80 2,624 1.5
CCDT-BEECH CIRCULAR 313.27 313.00 400 1
CDT-1001 CIRCULAR 286.28 285.72 274 3
CDT-1003 CIRCULAR 287.88 287.03 798 2.25
CDT-1005 CIRCULAR 289.50 288.13 806 2
CDT-1007 CIRCULAR 290.46 289.50 470 2
CDT-1009 CIRCULAR 280.50 278.50 119 3.5
CDT-1011 CIRCULAR 283.02 280.50 1,672 3.5
CDT-1015 CIRCULAR 286.22 284.79 945 2
CDT-1017 CIRCULAR 287.25 286.22 681 2
CDT-1019 CIRCULAR 287.60 287.25 203 2
CDT-1021 CIRCULAR 284.22 283.02 595 3.5
CDT-1023 CIRCULAR 297.05 284.72 133 3
CDT-1025 CIRCULAR 299.50 297.30 1,271 2.25
CDT-1029 CIRCULAR 300.80 300.20 917 2
CDT-1037 CIRCULAR 327.11 325.84 192 3.5
CDT-1039 CIRCULAR 329.97 328.11 597 2.5
CDT-1041 CIRCULAR 331.84 329.97 712 2.5
CDT-1043 CIRCULAR 333.59 332.34 611 2
CDT-1045 CIRCULAR 334.04 333.59 293 2
CDT-1047 CIRCULAR 332.98 332.34 427 2
CDT-1049 CIRCULAR 329.53 328.93 650 2
CDT-1051 CIRCULAR 339.63 328.93 470 2
CDT-1053 CIRCULAR 327.93 327.61 505 3
CDT-1057 CIRCULAR 331.47 330.69 382 3
CDT-1055 CIRCULAR 330.69 327.16 883 3
CDT-1013 CIRCULAR 284.79 284.52 174 2
CDT-1059 CIRCULAR 332.11 331.47 313 3
CDT-1061 CIRCULAR 333.51 333.11 198 2
CDT-1067 CIRCULAR 329.87 329.69 112 2
CDT-1069 CIRCULAR 329.69 328.00 128 2
CDT-1071 CIRCULAR 329.69 329.00 410 2
CDT-1073 CIRCULAR 337.96 335.49 833 2
CDT-1075 CIRCULAR 335.24 333.60 1,312 2.25
CDT-1077 CIRCULAR 336.28 335.21 656 2
CDT-1079 CIRCULAR 334.96 333.60 676 2.25
CDT-1081 CIRCULAR 331.40 330.41 891 2.5
CDT-1083 CIRCULAR 330.41 330.26 483 2.5
CDT-1085 CIRCULAR 327.58 327.00 194 3.5
Table E-2. Existing Conditions Conduits

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-20

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Conduit Name Type U/S Invert Elevation (ft) D/S Invert Elevation (ft) Length (ft) Diameter (ft) Table E-2. Existing Conditions Conduits
CDT-1087 CIRCULAR 327.75 327.58 616 3.5
CDT-1089 CIRCULAR 328.30 327.75 413 3.5
CDT-1091 CIRCULAR 328.64 328.30 223 3.5
CDT-1093 CIRCULAR 328.80 328.75 40 2.5
CDT-1095 CIRCULAR 329.13 328.80 781 2.5
CDT-1097 CIRCULAR 328.80 325.95 735 2.5
CDT-1099 CIRCULAR 325.95 324.88 703 2.5
CDT-1101 CIRCULAR 324.88 324.57 310 2.5
CDT-1107 CIRCULAR 335.00 331.00 1,982 2
CDT-1109 CIRCULAR 331.00 326.95 888 2
CDT-1111 CIRCULAR 325.95 324.24 1,416 3
CDT-1113 CIRCULAR 324.24 324.15 89 3
CDT-1117 CIRCULAR 325.07 324.65 408 2.5
CDT-1121 CIRCULAR 324.15 323.55 593 3
CDT-1129 CIRCULAR 324.00 320.03 260 2
CDT-1135 CIRCULAR 328.67 328.01 1,106 2
CDT-1137 CIRCULAR 328.01 328.00 10 2
CDT-1139 CIRCULAR 328.01 323.81 38 2
CDT-1141 CIRCULAR 323.43 323.61 170 2
CDT-1143 CIRCULAR 323.30 323.04 513 2
CDT-1145 CIRCULAR 323.04 323.00 38 2
CDT-1147 CIRCULAR 323.35 322.00 266 3
CDT-1149 CIRCULAR 323.70 323.35 392 3
CDT-1151 CIRCULAR 325.25 324.20 673 2.5
CDT-1153 CIRCULAR 326.80 325.75 698 2
CDT-1155 CIRCULAR 326.05 324.70 895 2
CDT-1157 CIRCULAR 294.18 293.80 103 2
CDT-1159 CIRCULAR 293.70 293.36 172 2.25
CDT-1167 CIRCULAR 289.36 288.83 533 4.5
CDT-1175 CIRCULAR 291.90 290.90 120 2.5
CDT-1183 CIRCULAR 294.78 291.71 621 3
CDT-1185 CIRCULAR 295.59 295.28 278 2.5
CDT-1187 CIRCULAR 296.03 295.59 556 2.5
CDT-1191 CIRCULAR 297.86 297.52 225 2
CDT-1193 CIRCULAR 291.90 288.50 210 1.5
CDT-1195 CIRCULAR 288.40 287.15 60 2.5
CDT-1199 CIRCULAR 292.13 286.80 99 2.5
CDT-1203 CIRCULAR 302.40 300.00 155 2
CDT-1205 CIRCULAR 302.45 302.40 693 2.5

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-21

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Conduit Name Type U/S Invert Elevation (ft) D/S Invert Elevation (ft) Length (ft) Diameter (ft) Table E-2. Existing Conditions Conduits
CDT-1207 CIRCULAR 301.40 300.09 1,436 3.5
CDT-1209 CIRCULAR 299.09 298.69 190 3.5
CDT-1211 CIRCULAR 298.69 298.02 807 3.5
CDT-1215 CIRCULAR 299.09 298.49 58 3.5
CDT-1217 CIRCULAR 293.54 290.36 2,032 3.5
CDT-1219 CIRCULAR 294.17 293.54 420 3.5
CDT-1221 CIRCULAR 295.98 295.17 528 2.5
CDT-1223 CIRCULAR 296.71 296.48 225 2
CDT-1225 CIRCULAR 296.90 295.98 606 2.5
CDT-1227 CIRCULAR 297.80 296.90 525 2.5
CDT-1229 CIRCULAR 295.42 295.17 800 2.5
CDT-1231 CIRCULAR 296.33 295.67 604 2.25
CDT-1233 CIRCULAR 306.60 302.77 1,286 2.5
CDT-1235 CIRCULAR 303.32 303.25 136 2.5
CDT-1237 CIRCULAR 303.25 302.77 735 2.5
CDT-1239 CIRCULAR 301.77 299.67 1,394 3.5
CDT-1245 CIRCULAR 299.67 299.16 1,282 3.5
CDT-1247 CIRCULAR 299.16 296.42 1,289 3.5
CDT-1257 CIRCULAR 288.30 287.40 587 2
CDT-1259 CIRCULAR 287.40 286.28 738 2
CDT-1261 CIRCULAR 287.40 286.28 737 2
CDT-1263 CIRCULAR 285.78 282.93 1,899 2.5
CDT-1265 CIRCULAR 291.73 283.43 594 2
CDT-1267 CIRCULAR 282.93 280.59 1,182 3
CDT-1275 CIRCULAR 302.66 301.00 433 4
CDT-1277 CIRCULAR 304.09 302.66 946 4
CDT-1279 CIRCULAR 306.25 304.09 1,436 4
CDT-1281 CIRCULAR 306.72 306.25 309 4
CDT-1283 CIRCULAR 308.65 306.72 871 4
CDT-1285 CIRCULAR 310.00 308.65 1,308 4
CDT-1287 CIRCULAR 311.86 310.00 1,239 4
CDT-1289 CIRCULAR 315.93 313.36 2,667 2.5
CDT-1291 CIRCULAR 314.72 313.86 571 2
CDT-1293 CIRCULAR 315.55 314.72 546 2
CDT-1295 CIRCULAR 315.71 315.55 106 2
CDT-1297 CIRCULAR 312.49 309.00 948 2
CDT-1299 CIRCULAR 309.54 308.25 854 2
CDT-1301 CIRCULAR 304.48 305.50 391 1.5
CDT-1303 CIRCULAR 308.48 307.98 451 3

CITY OF VISALIA
MASTER PLANS AND FINANCIAL NEXUS STUDY E-22

STORMWATER MASTER PLAN
AUGUST 2026 / FINAL DRAFT / CAROLLO
Conduit Name Type U/S Invert Elevation (ft) D/S Invert Elevation (ft) Length (ft) Diameter (ft) Table E-2. Existing Conditions Conduits
CDT-1305 CIRCULAR 310.00 308.48 933 3
CDT-1307 CIRCULAR 313.70 311.00 316 2
CDT-1309 CIRCULAR 312.89 311.00 796 2
CDT-1315 CIRCULAR 314.47 314.05 279 2
CDT-1317 CIRCULAR 314.72 314.47 167 2
CDT-1319 CIRCULAR 315.35 314.72 616 2
CDT-1321 CIRCULAR 317.61 316.42 795 2
CDT-1323 CIRCULAR 316.42 315.35 501 2
CDT-1325 CIRCULAR 314.01 313.70 304 2
CDT-1327 CIRCULAR 314.30 314.01 282 2
CDT-1329 CIRCULAR 314.55 314.30 248 2
CDT-1331 CIRCULAR 315.03 314.55 320 2
CDT-1333 CIRCULAR 315.42 315.03 252 2
CDT-1335 CIRCULAR 315.69 315.42 177 2
CDT-1337 CIRCULAR 316.02 315.69 219 2
CDT-1339 CIRCULAR 316.86 316.02 555 2
CDT-1343 CIRCULAR 298.43 297.54 595 2.5
CDT-1345 CIRCULAR 298.86 298.43 282 2.5
CDT-1347 CIRCULAR 299.30 298.86 296 2.5
CDT-1351 CIRCULAR 300.64 299.77 575 2.5
CDT-1353 CIRCULAR 302.04 300.89 600 2.25
CDT-1357 CIRCULAR 302.50 302.29 288 2
CDT-1359 CIRCULAR 304.30 302.50 331 2
CDT-1363 CIRCULAR 303.39 303.00 226 3
CDT-1365 CIRCULAR 304.17 303.39 514 3
CDT-1367 CIRCULAR 304.53 304.42 236 2.25
CDT-1369 CIRCULAR 305.18 304.78 426 2
CDT-1371 CIRCULAR 304.35 303.76 812 3
CDT-1373 CIRCULAR 304.67 304.35 150 2.5
CDT-1375 CIRCULAR 305.54 304.67 688 2.5
CDT-1377 CIRCULAR 305.67 305.54 282 2.5
CDT-1379 CIRCULAR 306.00 305.67 291 3
CDT-1381 CIRCULAR 306.99 306.00 1,159 2.5
CDT-1383 CIRCULAR 307.50 306.99 1,445 2
CDT-1389 CIRCULAR 305.19 299.09 237 2.5
CDT-1391 CIRCULAR 306.55 305.19 329 2.5
CDT-1393 CIRCULAR 309.53 307.05 1,650 2
CDT-1395 CIRCULAR 307.26 299.09 277 3.5
CDT-1397 CIRCULAR 308.96 307.76 1,327 3