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3. Maximum allowable depth of basin to be ten feet below the lowest gutter flow line with the bottom shaped to concentrate the water at the inlet and or outlet.
4. Basin will be fenced using six (6) foot fence or other approved standard, a twelve (12) foot wide double gate, and the fence may be located on the property line on all but exterior lots.
5. There will be a 3 ½ foot minimum unimproved walkway adjacent to the inside of the fence around the top of the basin.
6. Other requirements for a safe, aesthetic, maintenance and special conditions may be imposed by the City.
7. Detention basin pumping shall conform the requirements set forth by MID and/or per applicable drainage agreement with MID, when lVIlD facilities are utilized as outfall facilities.
S. Maximum allowable drain time for a IO-year, 24-hour storm in 72 hours.
9. Geotechnical and investigations and soils borings are required prior to design to determine sub-surface state, percolation rates and allowable or recommended depths.
10. Maximum allowable side slopes are 3:1 in non-joint-use basins, and 4:1 for facilities that incorporate park elements, except for the structural or aesthetic components.
7.04 PIPE MATERIALS
Storm drain pipe may be reinforced concrete pipe, non-reinforced concrete pipe, cast-in-place or concrete pipe, or polyvinylchloride pipe.
The type of pipe used must conform to accepted engineering practice and must be approved by the City Engineer. The class of pipe to be used shall be shown on the plans or specified in the special provisions.
Reinforced concrete pipe shall conform to Sections 65-1.02, 65-l.02A, 65-1.03, 65-1.06, 65-1.07 and 65-
1.08 of the State Standards.
Non-reinforced concrete pipe shall conform to Section 65-l.02A of the State Standards.
Cast-in-place concrete pipe shall conform to Sections 63-1.02, 63-1.03, 63-1.04, 63-1.05 and 63-1.06 of the State Standards and these Engineering Standards. Use of cast-in-place pipe shall be only as approved by the City Engineer with special trench requirements.
Polyvinylchloride (P.V.C.) pipe shall conform to ASTM D-3034 and SCR-35 minimum wall thickness.
7.05 DRAIN INLETS
Drain inlets shall be constructed as shown on Drawing No. SD-3.
The structural channel iron shall be galvanized to conform to the requirements of Section 75-1.05 of the State Standards.
Attachment D-2
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EROSION CONTROL
PIPE • DISCHARGE
SEE STD. DETAIL
NO. SD-10.
1%
15' RADIUS,
TYP.
1%
--- --
A
--
-----1------1 .,· _•
• ·.: --~,.
lf~R 5 :.>·f
SECTION A-A
12' MIN.t A
WROUGHT IRON FENCE SEE
STANDARD DETAIL . NO. M-5A
12' WIDE iPAVED ROAD ACCESS
FOR Cl7Y VEHICLES.
11Det~il ... . ·~JI~.·
11 ~ ..... -- I----0PENING1 ..,..__-+-
.v
DRAIN SYSTEMl II
II
---- ~------ -- -=- ~~anhole
NOTES:
-~- - ·.- -. -!t STREET
1. SIZE OF BASIN AND DEPTH TO BE DETERMINED BY HYDRAULIC CALCULATION.
HYDROSEED EXPQSE.D SOIL WITH NATIVE SEED .MIX AS APPROVED BY THE CITY ENGINEER.
STOR
Attachment E
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CITY OF LIVINGSTON
STORM DRAINAGE MASTER PLAN (REVISED FINAL VERSION - JULY, 2007)
5.0 Storm Drainage Infrastructure Plan (continued)
Considerations and Requirements Applicable to New Development In general, new development projects will be required to provide site-specific or project-specific storm drainage solutions that are consistent with the overall infrastructure approach presented in this Storm Drainage Master Plan. The City may allow for a reasonable degree of flexibility to be incorporated into specific design approaches as a part of achieving effective solutions. Any significant modifications to the elements of this Storm Drainage Master Plan must be approved by the City and will require that a formal "Supplement" be adopted by the City Council.
New development projects will be required to construct elements of the master plan infrastructure that have alignments that pass through them or extend along their project boundaries. The cost of construction of these master plan elements will be offset against other drainage funding requirements applicable to each project (such as drainage impact fees) in an appropriate manner. In some instances, the City may require or may accept the construction of offsite facilities or interim versions of master planned facilities as appropriate.
When new development projects are not located near existing or proposed terminal detention basins or outfalls leading to such terminal detention basins, the City may consider allowing the use of temporary storm drainage basins as an interim drainage solution, subject to appropriate engineering substantiation regarding feasibility. At the discretion of the City, the project developer may be required to maintain temporary storm drainage basins until the storm drainage system for the development project is connected to the City's permanent storm drainage system and the temporary storm drainage basin is filled and decommissioned. In the event that temporary storm drainage basins are approved by the City for individual or groups of development projects, said approvals will only be provided with the understanding or anticipation that a permanent solution that will allow for the decommissioning of applicable temporary storm drainage basins within a reasonable time frame is imminent.
The City may require that the developer deposit enough funds in advance with the City to pay for the future decommissioning of a temporary storm drainage basin.
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CITY OF LIVINGSTON
STORM DRAINAGE MASTER PLAN (REVISED FINAL VERSION - JULY, 2007)
6.0 Joint-Use Opportunities and Design Guidelines
The City has expressed a desire to avoid, where possible, the construction of new detention basins that serve no other function but to store and discharge storm runoff via pumping facilities or percolation. These single function facilities are eyesores and do not integrate well with adjacent development. Some retain water for long periods of time or indefinitely.
The consolidation of major storm water storage into a limited number of large detention basins provides the City with favorable opportunities for creating innovative grading and designs that incorporate recreation elements into the detention facilities. By adding lands allocated to storm water detention with lands allocated to parks, the City may effectively increase its available park land by utilizing functional joint-use design practices within consolidated facilities.
Many communities in the San Joaquin Valley have been able to effectively convert storm water lands to joint-use facilities that augment the community quality of life and aesthetic appeal as opposed to detracting from it.
An optimized joint-use detention basin will serve to:
• Maximize efficient use of land
• Satisfy detention needs for reducing peak flood flows • Provide water quality treatment
• Expand community recreational opportunities, with minimal "down time" for recreation elements
• Incur reasonable maintenance requirements and costs
• Serve as a functional open space amenity.
There are several fundamental guidelines that should be followed when incorporating recreation elements into storm water detention facilities. They are:
• Low flow must be accommodated in a manner that confines the frequent inundations to areas that will create minimal nuisance or disruption of recreational uses and will characteristically require only limited maintenance.
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CITY OF LIVINGSTON
STORM DRAINAGE MASTER PLAN (REVISED FINAL VERSION - JULY, 2007)
6.0 Joint-Use Opportunities and Design Guidelines (continued) • Contouring within detention facilities is recommended to create internal elevation variations (or tiers) that have differing frequencies and depths of inundation and differing flood risk.
• Internal drainage within detention facilities should provide for positive flow across elevated tiers and to the lowest lying areas of the facilities. • Internal slopes should be flat enough to allow for mowing of turf areas and to allow other routine recreational-related maintenance activities to occur. • Hydraulic design components should be included as needed (inflow structures, outflow structures, pump stations, sediment basins, spillways, surcharge structures, etc.).
• Other requirements as dictated by jurisdictional regulations and policies, local site conditions or additional functional uses should be followed.
In general, passive recreational elements should be incorporated in portions of detention facilities having the greatest potential flood risk and frequency. Active recreation elements are more suitable in areas within detention facilities having lesser degrees of flood risk and frequency.
Based on preliminary evaluations performed in conjunction with the preparer of the City's current Parks and Recreation Master Plan, the following is a general assessment of the joint-use potential for the major detention facilities serving each Drainage Zone:
Drainage Zone A- Good joint-use opportunity. Integrate with a community park.
Drainage Zone 8 - Good joint-use opportunity. Integrate with a neighborhood park.
Drainage Zone C - Integrate open fields (soccer fields) as joint-use elements.
Drainage Zones D and E - Could be integrated into a river corridor (along the Merced River), passive parkway or greenway with a trail system.
Drainage Zone F - integrate open fields, similar to Drainage Zone C.
Drainage Zone G and H - Reasonable joint-use opportunity to integrate with park lands.
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CITY OF LIVINGSTON
STORM DRAINAGE MASTER PLAN (REVISED FINAL VERSION - JULY, 2007)
6.0 Joint-Use Opportunities and Design Guidelines (continued) Drainage Zone I - There are limited recreational needs to be satisfied at this location, perhaps some neighborhood park uses may be added.
Drainage Zone J - Additional land area is needed to effectively integrate detention with community park facilities.
Drainage Zone K - This will be a large detention basin to be constructed in the future and is located in an area currently designated as an Urban Reserve land use. At such time as further detail is applied to land use planning for this area, the large size of the facility and location along Sultana Drive will provide for jointuse opportunities.
Drainage Zone L - The proposed terminal detention basin is located in a pieshaped corner formed by the intersection of Highway 99 and Peach Avenue/Liberty Avenue within an area currently designated for a Highway Commercial future land use. The terminal detention basin could be landscaped, including signage, to provide an entry statement for future land development projects in the area.
Also, existing Arakelian Park is a joint-use facility that, until recently, did not function as effectively as desired as low flow frequently entered the active recreation areas and interfered with recreational uses. This condition has been ameliorated by creating and diverting low flow to a new, deep area constructed within an expansion of the park area within the contiguous property to the north. 27 248 of 249
CITY OF LIVINGSTON
STORM DRAINAGE MASTER PLAN (REVISED FINAL VERSION - JULY, 2007) 7~0 Funding Alternatives
General
This SDMP identifies needs, priorities and costs for new and upgraded storm drainage facilities that are required to accommodate new development areas and relieve nuisance conditions in selected existing development areas. New and upgraded storm drainage facilities may consist of:
1. Facilities that serve existing development and are needed to correct existing deficiencies.
2. Facilities that are needed to serve new development.
3. Facilities that serve a combination of existing development and new development, with varying percentages of costs being attributable to accommodating new development and correcting existing deficiencies.
Given the above general scenarios, several approaches are available to the City for consideration regarding funding the desired capital improvements. Funding approaches may potentially consist of one or a combination of the following elements:
• Development Impact Fees (subject to Mitigation Fee Act known as AB 1600)
• Assessment District ( 1913115 Act)
• Special Tax Districts (Mello Roos Community Facilities District Act of 1982)
• Storm Drain Utility Fee (subject to Proposition 218)
Existing developed areas in the City could fund storm drainage facility improvements through adoption of a storm drain utility fee. This would be subject to the provisions of Proposition 218, the "Right to Vote on Taxes Act" of 1996.
New development can fund storm drainage improvements through a combination of development impact fees, assessment districts and special taxes. New development funds new and upgraded facilities, but they are not allowed to fund projects that fix existing deficiencies.
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CITY OF LIVINGSTON
STORM DRAINAGE MASTER PLAN (REVISED FINAL VERSION - JULY, 2007)
7.0 Funding Alternatives (continued)
Development Impact Fees
To the extent that new development creates a need for new and upgraded storm drainage facilities to accommodate the resultant increase in storm runoff caused by urbanization, the new development that utilizes these facilities will need to pay a fair share towards funding the required upgrades. See Section 8.0, "Impact Fees" for details.
Assessment Districts (1913/15 Act)
The potential exists for the establishment of one or more assessment districts to fund required storm drainage facilities and upgrades, where a common interest is shared by a large, but clearly defined group of constituents. The establishment of an assessment district requires a finding of direct and special benefit to the parcels being assessed, which shall be set forth in an Engineer's Report. Two public hearings and a mailed ballot are also required to establish an assessment district. If an assessment district is selected as a preferred financing mechanism, the SDMP may be utilized as a resource to assist in making the benefit findings required pursuant to Proposition 218 and preparing an Engineer's Report as part of formation of the district.
Special Tax- Mello Roos Community Facilities District (Act of 1982) If the City determines that more flexibility is needed in the allocation of costs and funding burdens, a Mello-Roos Community Facilities District (CFO) may be used instead of an assessment district. The Mello-Roos law does not require a finding of benefit for allocating costs among properties within the CFO, and the special tax can be spread in any "reasonable manner" according to the law. If a CFO is determined to be a more feasible funding tool, it will be necessary to prepare a Rate and Method of Apportionment of Special Tax for the CFO as a part of CFO formation and bond issuance. It does require a 2/3 approval of registered voters.
However, if less than 12 registered voters reside in the area, which is typical of undeveloped land, the special tax can be implemented with a property owner vote.
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