flood risk management cosgrove creek

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Flood Risk Flood Risk Management Management Cosgrove Creek Cosgrove Creek Section 205 Section 205 Planning Basics Planning Basics

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Flood Risk Management Cosgrove Creek. Section 205 Planning Basics. WHO we are/WHY we’re here. We are a Project Delivery Team (PDT) made up of engineers and scientists from the US Army Corps of Engineers We are teamed with our local cost-sharing sponsor, Calaveras County - PowerPoint PPT Presentation

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Page 1: Flood Risk Management Cosgrove Creek

Flood Risk Flood Risk ManagementManagement

Cosgrove Creek Cosgrove Creek Section 205Section 205

Planning BasicsPlanning Basics

Page 2: Flood Risk Management Cosgrove Creek

WHO we are/WHY we’re WHO we are/WHY we’re herehere

We are a Project Delivery Team (PDT) We are a Project Delivery Team (PDT) made up of engineers and scientists made up of engineers and scientists from the US Army Corps of Engineers from the US Army Corps of Engineers

We are teamed with our local cost-We are teamed with our local cost-sharing sponsor, Calaveras Countysharing sponsor, Calaveras County

This combined team will prepare a This combined team will prepare a Detailed Project Report (Feasibility Detailed Project Report (Feasibility report level) to resolve long term report level) to resolve long term problems with flood damages caused problems with flood damages caused by flash flooding along Cosgrove Creekby flash flooding along Cosgrove Creek

Page 3: Flood Risk Management Cosgrove Creek

WHO we are/WHY we’re WHO we are/WHY we’re herehere

This study is a follow up to an This study is a follow up to an approved Recon Report prepared in approved Recon Report prepared in 2005 which demonstrated Federal 2005 which demonstrated Federal interest in a comprehensive solutioninterest in a comprehensive solution

We will be looking at more alternative We will be looking at more alternative features and plans than previously features and plans than previously considered in the recon report considered in the recon report

This study will go well beyond any This study will go well beyond any maintenance clearing of the creekmaintenance clearing of the creek

Page 4: Flood Risk Management Cosgrove Creek

Meeting PurposeMeeting Purpose

Explain Federal participation:Explain Federal participation: Section 205 Project AuthoritySection 205 Project Authority NEPA process (CEQA)NEPA process (CEQA) Federal Policy and Planning Federal Policy and Planning

Parameters for study (Feasibility) Parameters for study (Feasibility) documentdocument

Listen to public comments and Listen to public comments and questionsquestions

Address concerns when possibleAddress concerns when possible

Page 5: Flood Risk Management Cosgrove Creek

AUTHORITYAUTHORITY

Continuing Authorities Program - Continuing Authorities Program - Section 205 of the Flood Control Act of Section 205 of the Flood Control Act of 1948 1948

Allows Secretary of the Army (via Chief Allows Secretary of the Army (via Chief Engineers) to plan, design, construct Engineers) to plan, design, construct certain water resource projects w/o certain water resource projects w/o additional Congressional approvaladditional Congressional approval

Cost share is 65% Federal NTE $7M Cost share is 65% Federal NTE $7M National limit for CAP is $50MNational limit for CAP is $50M

Page 6: Flood Risk Management Cosgrove Creek

BASIC BASIC REQUIREMENTSREQUIREMENTS

Sponsor (s) to provide 35% of project Sponsor (s) to provide 35% of project costs and any add’l dollars above costs and any add’l dollars above $7M$7M

Prepare Detailed Project Report Prepare Detailed Project Report (Feasibility Study) that demonstrates (Feasibility Study) that demonstrates project is economically justified. project is economically justified. Benefits > Costs (i.e., B/C > 1.0 *)Benefits > Costs (i.e., B/C > 1.0 *)

Re-affirm Federal Interest ( NED)Re-affirm Federal Interest ( NED) Comply with NEPA requirements Comply with NEPA requirements

Page 7: Flood Risk Management Cosgrove Creek

National Environmental National Environmental Policy ActPolicy Act

NEPANEPA NEPA is a Federal law that NEPA is a Federal law that

requires Federal agencies to requires Federal agencies to consider the environmental consider the environmental impacts of a proposed project impacts of a proposed project that is a major Federal action that is a major Federal action and that may have a significant and that may have a significant affect on the quality of the affect on the quality of the human environmenthuman environment

Page 8: Flood Risk Management Cosgrove Creek

NEPA GoalsNEPA Goals

Consider the environmental Consider the environmental consequences of a Federal action consequences of a Federal action before making a decisionbefore making a decision

Solicit and consider public views on Solicit and consider public views on the proposed action(s)the proposed action(s)

Provide government agencies with Provide government agencies with common mechanics to coordinate common mechanics to coordinate overlapping jurisdictional overlapping jurisdictional responsibilitiesresponsibilities

Page 9: Flood Risk Management Cosgrove Creek

NEPA definitionsNEPA definitions EA – Environmental Assessment; brief, EA – Environmental Assessment; brief,

documents the sufficiency of the information documents the sufficiency of the information used to determine environmental (including used to determine environmental (including human) impacts of a proposed Federal human) impacts of a proposed Federal action/project.action/project.

FONSI – Finding of No Significant Impacts – FONSI – Finding of No Significant Impacts – this is the official statement/result of the EA this is the official statement/result of the EA

EIS – Environmental Impact Statement takes EIS – Environmental Impact Statement takes longer to prepare as it is usually result of longer to prepare as it is usually result of serious controversyserious controversy

Mitigation – actions taken to compensate for Mitigation – actions taken to compensate for adverse environmental damagesadverse environmental damages

Page 10: Flood Risk Management Cosgrove Creek

6-STEP PLANNING 6-STEP PLANNING PROCESSPROCESS

ID PROBLEM and OPPORTUNITIESID PROBLEM and OPPORTUNITIES Note EXISTING and FUTURE (w/o Note EXISTING and FUTURE (w/o

project) conditionsproject) conditions FORMULATE ALTERNATIVE PLANSFORMULATE ALTERNATIVE PLANS EVALUATE alternative plansEVALUATE alternative plans COMPARECOMPARE SELECTSELECT

Page 11: Flood Risk Management Cosgrove Creek

COSGROVE CREEK COSGROVE CREEK STUDYSTUDY

PROBLEM:PROBLEM: Incidence and level of Incidence and level of damages caused by the existing damages caused by the existing periodic flooding of homes and periodic flooding of homes and businesses along lower third of businesses along lower third of Cosgrove Creek is increasing. Cosgrove Creek is increasing. Urbanization of the area is Urbanization of the area is exacerbating the problem. The exacerbating the problem. The periodic flooding also causes periodic flooding also causes streambank erosion resulting in streambank erosion resulting in excessive sedimentation downstream excessive sedimentation downstream threatening the health of the existing threatening the health of the existing riparian corridor.riparian corridor.

Page 12: Flood Risk Management Cosgrove Creek

STUDY PARAMETERSSTUDY PARAMETERS

Document to meet all policy Document to meet all policy requirements and follow 6-step requirements and follow 6-step planning process. The planning process. The GOALGOAL for this for this project is to:project is to:

““Reduce damages to both Reduce damages to both property owners and the natural property owners and the natural system that are adversely system that are adversely impacted by the periodic flooding impacted by the periodic flooding events along Cosgrove Creek”.events along Cosgrove Creek”.

Page 13: Flood Risk Management Cosgrove Creek

PROJECT OBJECTIVESPROJECT OBJECTIVES

Attenuate damaging peak flowsAttenuate damaging peak flows Stabilize creek banksStabilize creek banks Improve natural conditions that Improve natural conditions that

are favorable to wetlands and are favorable to wetlands and riparian habitatriparian habitat

Increase potential for Increase potential for recreational opportunitiesrecreational opportunities

Page 14: Flood Risk Management Cosgrove Creek

PROJECT CONSTRAINTSPROJECT CONSTRAINTS

Avoid adverse environmental impacts Avoid adverse environmental impacts (to include cultural resources, unless (to include cultural resources, unless these are considered minor and can these are considered minor and can be mitigated)be mitigated)

No adverse impacts to existing levels No adverse impacts to existing levels of flood damage reduction within of flood damage reduction within study area w/o appropriate study area w/o appropriate compensation compensation

No adverse impacts to Water QualityNo adverse impacts to Water Quality

Page 15: Flood Risk Management Cosgrove Creek
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POTENTIAL POTENTIAL ALTERNATIVESALTERNATIVES

No Action – what would happen in the No Action – what would happen in the future if no Federal project is future if no Federal project is implementedimplemented

Non-structural – cleanout channels Non-structural – cleanout channels (perhaps with minor re-shaping as (perhaps with minor re-shaping as necessary) add some property relocationsnecessary) add some property relocations

Build the detention alternative plan as Build the detention alternative plan as envisioned in the Reconenvisioned in the Recon

Build the retention alternative plan as Build the retention alternative plan as envisioned in the Reconenvisioned in the Recon

Page 18: Flood Risk Management Cosgrove Creek

POTENTIAL POTENTIAL ALTERNATIVESALTERNATIVES

Channelize Cosgrove Creek as needed Channelize Cosgrove Creek as needed (might be combination of earthen or (might be combination of earthen or concrete works; could be in just few concrete works; could be in just few problem areas)problem areas)

Divert peak flows towards New Hogan Divert peak flows towards New Hogan Lake (likely at some point upstream of Lake (likely at some point upstream of problem flooding area(s)problem flooding area(s)

Construct smaller retention/detention Construct smaller retention/detention areas where there might be room and areas where there might be room and need along the creek alignment.need along the creek alignment.

Page 19: Flood Risk Management Cosgrove Creek

POTENTIAL POTENTIAL ALTERNATIVESALTERNATIVES

Stabilize channel using:Stabilize channel using: Biotechnical measures such as fiber rolls, Biotechnical measures such as fiber rolls,

tree branch cuttings, log, rootwad, boulder tree branch cuttings, log, rootwad, boulder and/or tree revetments (these provide and/or tree revetments (these provide stability to the streambedstability to the streambed

Vertical grade controls (i.e. drop Vertical grade controls (i.e. drop structures)structures)

Flood terraces help to increase channel Flood terraces help to increase channel stability while providing riparian habitat stability while providing riparian habitat

___________(___________(Public InputPublic Input)____________)____________

Page 20: Flood Risk Management Cosgrove Creek

ISSUES/CONCERNSISSUES/CONCERNS Dynamic urbanization by developers is Dynamic urbanization by developers is

resulting in a “piecemeal” approach to flood resulting in a “piecemeal” approach to flood reduction. Cumulative effects become reduction. Cumulative effects become difficult to assess.difficult to assess.

Land use changes to urbanization is resulting Land use changes to urbanization is resulting in increased nutrients into the creek in increased nutrients into the creek resulting in greater vegetation restricting resulting in greater vegetation restricting water movementwater movement

Maintenance issues within creek exacerbated Maintenance issues within creek exacerbated by potential Red-legged frog habitatby potential Red-legged frog habitat

________(________(Public Input)Public Input)____________________

Page 21: Flood Risk Management Cosgrove Creek

WHAT’S NEXT?WHAT’S NEXT?

Capture public and interagency scoping inputCapture public and interagency scoping input Prepare detailed project schedule (Corps Prepare detailed project schedule (Corps

requirement)requirement) Procure environmental services needed to Procure environmental services needed to

address ESA concerns (i.e., Red-legged frog, address ESA concerns (i.e., Red-legged frog, etc.)etc.)

Develop preliminary suite of alternative plansDevelop preliminary suite of alternative plans Post interim updates monthly on County Post interim updates monthly on County

websitewebsite Next public meeting – 6-9 months from nowNext public meeting – 6-9 months from now