1 CAP SECTION 103 FACT SHEET
(As of 30 March 2022, for TSP Milestone)
1. Project Name: Lower Colma Creek CAP 103
2. a. Corps District: San Francisco District
b. Sponsor: City of South San Francisco, working through the South San Francisco Water Quality Control Plant (SSF WQCP)
3. Congressional Delegation: U.S. House of Representatives Congressional District 14 (CA):
Representative Jackie Speier, Democrat; U.S. Senate: Senators Dianne Feinstein and Alex Padilla
4. Location: The SSF WQCP is in the City of South San Francisco, CA (SSF), which is part of San Mateo County. South San Francisco is bordered by the cities of Brisbane to the north and San Bruno to the south. The SSF WQCP is located on the right bank of the Lower Colma Creek where it meets San Francisco Bay (see Figure 1). The San Francisco Bay is tidally influenced with connection to the Pacific Ocean through an inlet by San Francisco and the Golden Gate Bridge, north of the project area (see Error! Reference source not found.).
Figure 1. The South San Francisco Wastewater Quality Control Plant and nearest sanitary pump stations are located just north of San Francisco International Airport, along Colma Creek and San Francisco Bay.
2 Figure 3 shows the service area of the SSF WQCP, which includes 165,000 full time residents, plus the daily population of the San Francisco International Airport (SFO) that rely on the plant. Disadvantaged communities and socially vulnerable groups make up a significant portion of the study area in San Bruno and South San Francisco. The study area also comprises affluent and majority white communities, such as Burlingame.
Figure 2. Project Area Location. The WQCP is located along San Francisco Bay, which is tidally influenced via the connection to the Pacific Ocean north and west of the project. Source: GoogleMaps San Francisco
Bay
Pacific
Ocean
3 Figure 3. Service area by treatment/service type of the South San Francisco Wastewater Quality Control Plant
4 5. Problem:
Problems.
1. Storm driven waves and currents cause coastal flood risk to the SSF WQCP which risks economic damages resulting from damage to infrastructure and contents, plant service shutdown, and cleanup costs from the backup of untreated effluent in homes, businesses, and streets throughout the service area.
2. Should significant flooding occur at the SSF WQCP or at pump station 4, there is a risk of service disruption to their roughly 112,000 customers resulting in potential business and household economic losses.
3. Public and environmental health is at risk should coastal flooding cause the need for emergency releases of untreated effluent into Colma Creek and San Francisco Bay.
4. The coastal flood risk endangers human life and safety of the WQCP workers and operators should the plant flood.
5. Human safety is endangered from direct exposure to untreated sewage backing up in the sewer system and overflowing in toilets and manholes in the service area of the SSF WQCP in the event of a plant shutdown caused by coastal flooding.
Opportunities.
1. There is an opportunity to avoid or reduce discharges of untreated effluent into the Bay and avoid water quality degradation and associated impacts to human health and the environment.
Opportunities to improve habitat values and the aesthetic and recreational experience in the study area were also investigated.
Planning Objectives.
1. Manage the risk of flooding at the SSF WQCP and its pump stations.
2. Manage risk to human life and safety due to flooding at the SSF WQCP and its pump stations.
3. Reduce the economic damages that result from flooding of the WQCP (including pump stations), and the associated potential service disruptions and/or plant shutdowns.
4. Reduce damages to the environment (people and other living things) that result from flooding and the associated releases of untreated effluent into Colma Creek or San Francisco Bay.
Planning Constraints.
1. The project cannot compromise the safety and security of the SSF WQCP, which is critical infrastructure for the region.
2. There is also the universal constraint that the project must comply with applicable federal laws, regulations and policies.
6. Alternative Plans Considered:
Eleven structural measures, seven non-structural measures, and one recreation measure were identified for initial consideration. The team used existing information, or rough calculations to screen the least promising measures from further consideration. Alternatives or measures which exceeded the cost limit for the CAP, or which were not constructible due to lack of space, or were determined to be ineffective means for achieving the objectives of the project were not carried forward. Five measures were ultimately retained and 16 were screened out. Two non-structural 5 measures were screened for some application, but retained for more limited application, such as raising the electrical system and emergency exits only.
Table 1 summarizes the measures which were retained:
Table 1. Summary of Measure Screening and Rationale for Lower Colma Creek 103 Measure (type of measure) Retained /
Screened
Rationale/Reason
Floodwall (structural) Retained There is sufficient space to site a floodwall and cost estimate is within CAP cost limit. Alignment
can be pulled back from shoreline as much as
possible to avoid impacts to adjacent marsh near
bridge on north end of WQCP. Floodwalls are
compatible with plant operability.
Flood proofing of key
structures (non-structural)
Retained Depths of flooding are shallow and velocities are low, which makes flood proofing a viable potential
measure. Cost is competitive compared to other
measures. SLR adaptability would be to seal plant
more frequently. May impact operability and
performance of plant, which needs investigation.
Operating during flood conditions could endanger
workers at the plant, so a safety assessment is
needed.
Flood warning system (nonstructural) Retained For the non-structural operation, the flood warning system is necessary to ensure all flood proofed
doors, windows, and stop log vehicular access gate
are closed. Because these facilities will be used
daily, with doors and gates opened for access,
these would need to be closed for the nonstructural plan to be effective.
Ring Levee (non-structural) Screened for
main WQCP
Retained for
pump station 4
Insufficient space
For pump station 4, there is room for a small
retaining wall type concrete floodwall around the
perimeter station, with a stop log gate for vehicular
access. Cost is well within CAP cost limit.
Raise critical assets in place
(non-structural)
Screened for
most assets
Retained for
electrical
system only
Infeasible/not cost effective compared with
floodproofing
It is not feasible to floodproof the entire network of
subterranean electrical system, which is
particularly hazardous if flooded. Raising electrical
only was retained.
The initial evaluation of measures found the recreation and nature-based coastal storm risk management options to be limited yet expensive, so these measures were not carried forward. In combining measures into alternatives, the team sought to establish a range of risk management via a smaller floodwall alignment on only the lowest lying side of the plant (north side of the plant only), tying into high ground, and a second more comprehensive alignment that included a floodwall along the southern side of the plant 6 as well (see Figure 5). The remaining boundaries of the plant were determined to be either sufficiently high in elevation to not require a floodwall, as they did not overtop for any scenario that was modeled; or in the case of the finger piers, to flood slightly during some modeled events but to not cause significant damages. Where the San Francisco Bay Trail crosses the alignment by the Costco parking lot, the elevation is already high. There is a low spot directly east of that which would be filled to raise it to the minimum elevation, to not create a low point where water can flow across the floodwall. The trail would therefore be unimpeded and continue to allow recreation. The floodwall would tie into the trail just east of where the green line begins in the left of Figure 4. This floodwall would vary in height above grade based on the ground elevation, but is roughly three to four feet high.
Figure 4. The floodwall on the North side of the WQCP is included in Alternatives 1 and 2, and would extend from the creek side of Costco, east to tie into higher elevation by the eastern side of the plant. The SF Bay Trail will not be impeded.
7 Figure 5. Alternative 2 also includes a shorter floodwall along the southern edge of the plant where elevations are lower, in addition to the north wall shown in Figure 4.
Figure 6. Alternatives 1, 2, and 3 all include a ring floodwall at sanitary pump station 4, which is roughly 2 feet high at grade, with a stop log gate which would need to be closed in a flood event to keep water out.
There is no critical infrastructure at risk in the finger pier location. The finger piers are currently used by the City of South San Francisco for miscellaneous storage, for example old street lights, and overflow airport parking by the leasee Park SFO, who operates a large parking garage further upland from the finger piers (see Figure 1). Damages in this location are not significant enough to justify measures here, and these uses could be relocated to avoid flood damages. The existing marsh that fringes the WQCP, and the finger piers were identified as potential mitigation locations for this project. 8 Both floodwall alternatives and the non-structural alternative include a non-structural measure of a small ring floodwall around pump station 4, which was determined to be at high risk from flooding. This will likely be a small-scale sheetpile I-wall which does not require excavation, roughly two feet high at grade on average, with a stop log gate to provide vehicular access. The subterranean control room and infrastructure at this location result in high consequences from flooding, including sewage backups into residences and streets, flowing through manholes and toilets.
Floodproofing Pump Station 4 was determined to be infeasible, and a smaller perimeter alignment was considered, but determined to impede operations as vehicles access the grated access panels. Flood proofing was not feasible to protect the “at-grade” 480Volt Motor Control Center (MCC), a 12kV utility power (PG&E) transformer, an emergency standby-by power generator, and multiple subgrade conduit vaults that connect the station’s equipment to their respective power sources. These structures would be inundated with flood water, causing all utility and emergency backup power supplied to the station to fail.
This would ultimately cease operation of the station to convey sewage, subsequently, causing the station to overflow. Thus, a full perimeter wall, 2 feet above grade on average, with stop log vehicular gate access, was included. An early flood warning system is also necessary to ensure that the stop log gate is sealed prior to flood waters reaching them.
Final Array of Alternatives.
Three alternatives were included in the final array for final comparison, plus a No Action alternative. The non-federal sponsor did not request consideration of a Locally Preferred Plan. The non-structural only plan is not implementable within the CAP cost limit, but was retained per the requirement to include a complete nonstructural only plan in the final array of alternatives for flood risk projects within USACE.
No Action Alternative—in this scenario, the federal government would take no action to address coastal flood risk at the SSF WQCP and pump stations. Coastal flood risk would increase over time.
Alternative 1—the North Floodwall Alternative includes an I-wall (sheetpile) floodwall, approximately 3 to 4 feet above grade at WQCP at the north side of the WQCP adjacent to the right-bank of Creek. At Pump Station 4, a perimeter sheetpile floodwall, approximately 2 feet above grade, would be constructed, with stop log gate for vehicular access and early warning system so that plant operators would know when to seal the stop log gate.
Alternative 2—the North and South Floodwall Alternative includes an I-wall (sheetpile) floodwall, approximately 3 to 4.5 feet above grade at WQCP at the north side of the WQCP adjacent to the rightbank of Creek, as well as a second shorter approximately two-foot-high floodwall south of plant adjacent to San Francisco Bay. At Pump Station 4, a perimeter sheetpile floodwall, approximately 2 feet above grade, would be constructed, with stop log gate for vehicular access and early warning system so that plant operators would know when to seal the stop log gate.
Alternative 3—Nonstructural Only Alternative would dry floodproof 23 structures at the main WQCP by installing water tights doors and windows and using membranes to waterproof structures. The subterranean interconnected electrical system is not practicable to flood proof and would need to be elevated, as it is currently all subterranean. This plan also includes a low floodwall, roughly 2 feet high, and stop log gate around Pump Station 4, and add flood warning system to alert plant staff when to close the stop log gate, similar to Alternatives 1 and 2. To be complete, this alternative would likely also require elevated exit doors and walkways to allow plant operators to maneuver between buildings to operate the plant and allow safe egress during flood events. However, the cost for elevated walkways and exits was not included in the cost estimate for this alternative, which is already orders of magnitude more costly. This would only add to the cost.
9 The evaluation of the Final Array of Alternatives for how effective, efficient and acceptable they are is summarized in Table 2. The team used existing analysis, collective expertise and professional judgement to assess and evaluate the alternatives. The metrics are noted in the Tables 1 and 2. Where the metrics are qualitative, the rationale for ranking is explained.
Effectiveness measures how well the plans meet the primary CSRM objectives of the project, and how feasible they are to construct, etc. Effectiveness at meeting objectives was discussed by the team for each objective. All the alternatives were determined to be highly effective for addressing objectives 2 and 3, based on the initial assessment. For managing risk to human life and safety, the team had concerns that Alternative 3 could pose safety hazards to plant operators who were going between buildings and operating the plant when up to 3.77 feet of floodwaters surround the buildings. Measures to manage this risk for Alternative 3 were added, such as raising the electrical system and elevated exits and walkways.
Nonetheless, the team concluded that Alternative 3 was less safe to plant operators, than the structural alternatives where there is less risk of floodwaters entering the plant property and endangering operator safety. The plant operators would need to evacuate should the risk of overtopping occur for Alternatives 2 and 3.
Efficiency was analyzed in the context of cost effectiveness, in this case initially using rough costs and then again using net NED benefits. Acceptability refers to whether the plan is legally implementable.
Alternative 2 ranked high in all categories, followed by Alternative 1, which ranked high in all but efficiency, where it ranked medium because it has fewer net benefits than Alternative 2. Alternative 3 was low in efficiency due to the very high cost of $72 million before a 107% contingency is added. The contingency was developed during an Abbreviated Cost and Schedule Risk Analysis which documents great uncertainty and complexity associated with final design and cost of this alternative. Alternative 3 also ranked medium for constructability, as it involves specialized construction, and medium for life safety since plant operators would be operating the plant in a flood condition, with water surrounding the buildings.
10 Table 2. Comparison and Evaluation of the Final Array of Alternatives Screening Criteria: Effectiveness
Achieves Primary Objective to Manage Coastal
Flood Risk
Screening
Criteria:
Effectiveness
Screening
Criteria:
Efficiency
Screening
Criteria:
Completeness
Screening
Criteria:
Acceptability
Qualitative Ranking
Categories
Green = High
Yellow = Med
Red= Low
Primary
Project
Objective #1:
Manage risk
to human life
and safety
Primary
Project
Objective #2:
Reduce
Economic
Damages from
Flooding
Primary Project
Objective #3:
Reduce damages
to env from
flooding and
effluent releases
Feasible /
Constructable
(High/
Medium/
Low)
Cost
Effectiveness
($/Net
Benefits)
Benefits
Realized
Without
Further
Action From
Others
(Yes/No)
Legally
Implementable
(Yes/ Yes, but
requires
significant
coordination /
No)
Alternative 1: North
Floodwall + Pump
Station 4
Alternative 2: North
& South Floodwall
+ Pump Station 4
Alternative 3:
Nonstructural Only
- Raise electrical
system + Flood
proofing + Pump
Station 4
11 Table 3. Comprehensive Benefit Evaluation and Comparison of Final Array of Alternatives
Screening
Criteria #1:
Efficiency ($
cost effective $)
Screening
Criteria #2:
Effectiveness
(meets primary
objectives)
Screening
Criteria #3:
Acceptable
(Implementable)
Screening
Criteria #4:
Completeness
(standalone)
Screening
Criteria #5a:
Environmental
Quality (EQ)
habitat
Screening
Criteria #5b:
Environmental
Quality (EQ)
Cultural
Resources
Screening
Criteria #6a:
Other Social
Effects (OSE),
life safety
Screening
Criteria #6b:
Other Social
Effects (OSE),
environmental
justice
Screening
Criteria #6c:
Other Social
Effects (OSE),
impact to
people/society of
raw sewage
exposure
Screening
Criteria #7:
Operability
Screening
Criteria #8:
Performance
Final Array of
Alternatives
Green = High
Yellow = Med
Red = Low
Green = High
Yellow = Med
Red = Low
Green = High
Yellow = Med
Red = Low
Green = Yes
Yellow =
Complete for
all but the
very
infrequent
flood events
where plant
workers would
leave due to
safety and
plant would
shut down
Red= No
Green = High
Yellow = Med
Red = Low
Green = No
impacts to
Cultural
Resources
Yellow =
Medium
impacts to
cultural
resources
Red= High
impacts
Green =
manages risk
Orange =
Unsure/medium
Red = Negative
Impact
Green =
Equitable
benefits/damages
and avoids
impacts to
vulnerable
Orange =
Unsure/medium
Red = Negative
or Unequitable
Impact/Benefits
Green =
Equitable
benefits/damages
and avoids
impacts to
vulnerable
Orange =
Unsure/medium
Red = Negative
or Unequitable
Impact/Benefits
Green =
High
Yellow =
Med
Red = Low
Green =
High
Yellow =
Med
Red = Low
Alternative 1:
North Floodwall +
Ring Floodwall at
Pump Station 4
with gate + flood
warning system
Alternative 2:
North & South
Floodwall + Ring
Floodwall at Pump
Station 4 with gate
+ flood warning
system
Alternative 3:
Nonstructural
Only - Raise
electrical system +
Flood proofing 23
structures + ring
floodwall at Pump
Station 4 + Flood
warning system
Table 3 summarizes the comprehensive benefit screening that the team performed to identify a plan that maximizes benefits across all benefit categories. The four benefit accounts that the USACE analyzes are National Economic Development (NED), Environmental Quality (EQ), Other Social Effects (OSE), and Regional Economic Development (RED). While the primary objectives of the study are all related to managing the risk of flooding due to coastal storms and tide driven events, the team looked to maximize the benefits that our alternatives could provide. OSE was an important benefit category for this project due to the serious impact to people and society that would come from large scale raw sewage exposure and contamination in homes and streets, which this project aims to manage the risk of. There were also life safety components to consider for plant operators, since an objective of the study is to keep the plant operational during a coastal storm, plant operators would need to be able to safety remain on site, without undue risk to their lives. Finally, much of the communities that this WQCP services are socially vulnerable communities who have been historically disadvantaged. Impacts to these communities can be harder to recover from as they may have less resources, options, and access to services. 12 Operability was included as the nonstructural alternative would alter the way the WQCP operates in both a normal and flood environment, and would require changes to how the operators move around the plant and between buildings, as well as how the electrical system functions. The work to elevate the electrical system may require periodic outages during construction, which would impact plant performance. Plant performance would also be impacted if the plant operators needed to evacuate the plant due to unsafe flooding, which is more likely in Alternatives 1 and 3. EQ analysis was broken into comparison of each plan to habitat EQ and cultural resources EQ, as they performed differently. Cultural resources EQ is negatively impacted by more ground disturbance, so Alternatives 1 and 2 which include structural work near the banks have the possibility of disturbing buried cultural artifacts or tribal human remains. The EQ benefits for habitat are tied to avoiding emergency releases of untreated effluent into Colma Creek and San Francisco Bay. In that sense, Alternatives 2 and 3 are more effective, than Alternative 1 which mitigates less risk than Alternatives 2 and 3.
7. Description of Likely Recommended Plan.
The likely recommended plan is Alternative 2 which is the NED Plan and the plan that maximizes benefits across all four benefit accounts. It is also the preferred plan on the non-federal sponsor.
Alternative 2 meets the CSRM objectives of managing risk to human life and safety by managing the risk of the WQCP and Pump Station 4 flooding, up to an extreme tide elevation of 12.34 ft during a
0.2% AEP event with 50 years at the Intermediate SLR rate from the base year of 2023, with a wall crest elevation of 13.5 ft. This prevents flooding through the low spots on the north side from the Colma Creek channel and through the low spots on the south side of the WQCP area. The WQCP is still susceptible to overland flow from the west, but this flooding was found to enter the WQCP area only at extreme tide elevations greater than 13 ft. This would allow plant operators to keep the plant operational and avoid emergency releases of raw sewage into Colma Creek and San Francisco Bay due to plant shutdowns. It would also manage the risk of coastal flooding causing raw sewage to back up into homes and streets if pump stations were to fail or the plant were to not be able to accept pumped sewage. Alternative 2 reduces economic damages that could occur annually by $774,843 and has annual net benefits of $340,612 and a benefit to cost ratio of 1.78. It improves resiliency to sea level rise for the project area region. The likely recommended plan also improves social justice by managing risk of impacts to human health and safety, as well as aesthetic impacts of raw sewage in socially disadvantaged communities.
Finally, Alternative 2 is relatively straightforward and simple to implement, with the majority of construction and staging occurring on WQCP property, limited excavation required, and low and mitigatable impacts to habitat and cultural resources. Because the sheetpile I-walls with concrete caps proposed for Alternatives 1 and 2 cannot be raised later, they are not inherently adaptable. While Alternative 1 is still vulnerable to 0.2% AEP events with 20-50 years at the Intermediate SLR rate from the base year of 2023, Alternative 2 manages risk including 0.2% annual chance events with 50 years at the Intermediate SLR rate from the base year of 2023. Alternative 1 is vulnerable to 10% AEP events with 50 years at the High SLR rate and 0.2% AEP events with 25 years at the High SLR rate, while Alternative 2 is vulnerable only at 0.2% AEP events with 50 years at the High SLR rate. In this sense, Alternative 2 reduces the risk of needing future adaptation based on higher rates of future SLR, and is a more resilient plan. Because the additional cost for this added resiliency is not very high, the net benefits from the project increase with this added increment.
Alternative 2 is also implementable within the CAP cost limit and authority.
8. As of the date of this fact sheet, are there any policy waivers required, including a waiver for deviation from the NED Plan? No
13 9. Schedule (key milestones):
Execution of FCSA: November 2020 (A)
Approval of Feasibility Study: September 2022 (S)
Initial Construction Award (FY): September 2023 (S)
10. Study Authority. CAP Section 103 of the Rivers and Harbors Act of 1962, as amended (33 USC 426g), authorizes the USACE to study, adopt and construct continuing authority beach erosion control (coastal storm risk reduction) projects. Per ER 1105-2-100: “This authority may be used for protecting multiple public and private properties and facilities and single non-Federal public properties and facilities against damages caused by storm driven waves and currents.” The maximum total federal expenditure for a Section 103 project cannot exceed $10,000,000. This study was initiated by a request from the City of South San Francisco, CA, who is the non-federal sponsor.
11. Financial Information.
Description Alt 1 ($FY21) Alt 2 ($FY21) Alt 3 ($FY21)
Feasibility Study Cost $1,170,000 $1,170,000 $1,170,000 Federal Share $585,000 $585,000 $585,000
Non-Federal Share $585,000 $585,000 $585,000
Initial Construction Costs $10,235,000 $12,955,000 $72,041,199 Federal Share $6,652,750 $8,420,750 $46,826,799
Non-Federal Share $3,582,250 $4,534,250 $25,514,419
LERRD Costs TBD TBD TBD
Total Federal Cost $7,237,750 $9,005,750 $47,411,779
Annual Net NED Benefits $182,989 $340,612 -$1,655,044
Benefit-Cost Ratio 1.53 1.78 0.31
Average Annual O&M Costs TBD TBD TBD
12. Complete Funding History / Projected Outlook by FY:
FY21 - $100k (Initiate Feasibility – prepare FID & PMP/FCSA) FY22 - $585k (Feasibility)
FY23 - $200K (Feasibility Report approval)
FY24 - $9M (P&S, Contract award & construction)
13. Supplemental Information.
a. Environmental Setting:
Colma Creek in the study area is a tidal channel that has water in it year-round. It has hardened banks, bars with marsh vegetation and mudflats that are exposed at low tide. It provides habitat for mixed assemblage of native and nonnative fish, wildlife, plant and invertebrate species typical to the region.
The project area marshes are isolated from larger contiguous marsh areas to the south and east. The National Oceanic and Atmospheric Administration’s National Marine Fisheries Service (NOAA 14 Fisheries) multispecies salmonid recovery plan does not identify Colma Creek as suitable or critical habitat for steelhead, Coho, or Chinook salmon (Oncorhynchus spp.).
The project area consists entirely of previously developed or landscaped areas within the existing WQCP and is adjacent to tidal portions of Colma Creek, the San Bruno Slough, the San Bruno Canal and the San Francisco Bay shoreline. The surrounding land uses are generally industrial in nature.
The proposed project components are not directly located in areas supporting special-status plants or wildlife or designated critical habitat.
b. Real Estate:
Land, Easements, Rights-of-Way, Relocation, and Disposal Areas (LERRDs): There are no impacted utilities/facilities that require relocation identified at this time. Lands include the WQCP and Pump Station #4 facilities. The real estate cost estimate for the TSP was developed in accordance with ER 405-1-12 and based upon footprints delineating project requirements developed for feasibility level design by the San Francisco District Engineering Division. The two variations for structural alternatives (Alternative 1 and Alternative 2) were reviewed for LERRDs requirements and include the types of acquisition as follows:
An estimated 0.33 acre is required for staging.
An estimated 0.27 acre is required for construction.
The non-Federal sponsor will acquire the minimum interests in real estate to support the construction and subsequent operation and maintenance of the future USACE project. USACE Real Estate Division anticipates Perpetual and Temporary Easement acquisition will be required.
Once the project partnership agreement (PPA) process is complete, the San Francisco District Engineering Division will prepare the final design for advertisement and construction. During this process the tract register, and tract maps will be updated to reflect any modifications to include final staging areas, access requirements, construction haul routes, and recreation features. This information will be used for review of future crediting purposes. c. Monitoring and O&M:
The Operations & Maintenance (O&M) of this project will be at 100% non-federal expense, however USACE will perform inspections. The Inspection of Completed Works (ICW) program is an O&M program that provides for USACE inspections of federally constructed flood risk management projects. A draft O&M manual will be developed preceding a project’s final design state and used by the counties and the USACE to ensure that the project is maintained to USACE standards. Annual and periodic 5-year ICW inspections will be performed for the Lower Colma Creek Project which will be based on the O&M manual requirements and current USACE maintenance standards. The O&M manual will provide a detailed description of the management activities for the floodwall, channel, vegetation, sediment, debris, bank erosion, concrete surfaces, and other activities to provide the design flood risk management of the TSP. If the project is required to provide compensatory mitigation for unavoidable impacts, a mitigation and monitoring plan will be prepared prior to release of the draft report.