Prioritization Next Steps 10182011 revPrioritization S 1 Post‐screening project types Low...

Sonoma Valley Stormwater Management and Groundwater Recharge Scoping Study

Prioritization & Next Steps

Betty AndrewsPrincipalp

bandrews@esassoc.com

www.sonomacountywater.org

Screen and prioritizeScreen and prioritize

Project typesinventory Stakeholder ideas

screen Likelihood of achievement of both

Likelihood of physical feasibility:

Fair or better 

inventory

screen achievement of both core objectivesrecharge 

geology

Slope < 10%

Siting feasibilityAbsence of 

significant water quality concernsprioritize

Low likelihood of significant regulatory 

constraintsMagnitude of

Expected cost/units of core objective 

benefit

Ability to meet supporting objectives

Magnitude of potential core 

benefits

Short list of potential project concepts (type, location)

Prioritization

S 1 S 2 S 3

Absence of i ifi

Low likelihood of i ifi l

Magnitude of 

Step 1 Step 2 Step 3

Ability to meet 

significant water quality concernsprioritize

significant regulatory constraints

potential core benefits

Expected 

Siting feasibility supporting objectives

cost/units of core objective benefit

Short list of potential project concepts (type, location)

PrioritizationPrioritization

S 1Post‐screening project types

/ /

Low likelihood of i ifi l

Step 1 In‐line detention/retention/recharge basinsOff‐line detention/retention/recharge 

prioritizesignificant regulatory 

constraintsbasinHigh flow diversion/recharge

Floodplain attenuation/recharge

Expected cost/units 

Siting feasibilityFloodplain attenuation/recharge

Above‐ground or underground storage tank/rechargeI fil i ll /d iof core objective 

benefitInfiltration gallery/detention

Self‐cleaning infiltration trench/detention

LID

PrioritizationPrioritization

S 1Post‐screening project types

/ /

Low likelihood of i ifi l

Step 1 In‐line detention/retention/recharge basinsOff‐line detention/retention/recharge 

prioritizesignificant regulatory 

constraintsbasinHigh flow diversion/recharge

Floodplain attenuation/recharge

Expected cost/units 

Siting feasibilityFloodplain attenuation/recharge

Above‐ground or underground storage tank/rechargeI fil i ll /d iof core objective 

benefitInfiltration gallery/detention

Self‐cleaning infiltration trench/detention

LID

PrioritizationPrioritization

S 1Post‐screening project types

/ /

Low likelihood of i ifi l

Step 1 In‐line detention/retention/recharge basinsOff‐line detention/retention/recharge 

prioritizesignificant regulatory 

constraintsbasinHigh flow diversion/recharge

Floodplain attenuation/recharge

Expected cost/units 

Siting feasibilityFloodplain attenuation/recharge

Above‐ground or underground storage tank/rechargeI fil i ll /d iof core objective 

benefitInfiltration gallery/detention

Self‐cleaning infiltration trench/detention

LID

Prioritization

Project types LocationsOff‐line basin Sonoma Creek at Lawndale

Step 1 Sonoma Creek above Calabasas Creek Calabasas Creek at Sonoma Creek Sonoma Creek at Agua Caliente Road Sonoma Creek below Dowdall Creek Nathanson Creek at Schell Creek Fowler Creek above Rodgers Creek Arroyo Seco at Schell Creek Rodgers Creek at Fowler Creek

High flow di i / h

Sonoma Creek at Lawndalediversion/recharge Nathanson Creek at Schell Creek

Infiltration gallery  (Subbasins as listed for off‐line basins)Self‐cleaning infiltrationSelf cleaning infiltration 

trench(Subbasins as listed for off‐line basins)

LID (Subbasins as listed for off‐line basins)Table 3:

PrioritizationPrioritizationPost‐screening project types

/ /In‐line detention/retention/recharge basinsOff‐line detention/retention/recharge 

prioritize

Step 2

basinHigh flow diversion/recharge

Floodplain attenuation/recharge

Magnitude of potential core

Step 2 Floodplain attenuation/recharge

Above‐ground or underground storage tank/rechargeI fil i ll /d ipotential core 

benefitsInfiltration gallery/detention

Self‐cleaning infiltration trench/detention

LID

PrioritizationPrioritization

Best location for flood prioritize

Step 2

hazard reduction 

Step 2

Magnitude of potential core

Best location for groundwater recharge

potential core benefits

PrioritizationPrioritization

prioritize

Step 2Step 2

Best location for flood h d dhazard reduction 

PrioritizationPrioritization

prioritize

Step 2Step 2

Best location for d hgroundwater recharge

Prioritization

Project types LocationsOff‐line basin In lower‐slope recharge‐suitable

Step 2Off line basin In lower slope, recharge suitable 

portions of the following subbasins: 

Sonoma Creek at LawndaleSonoma Creek at Lawndale Sonoma Creek below Dowdall

Creek Nathanson Creek at Schell 

CreekHigh‐flow diversion/ 

rechargeApproximately along existing 

high‐flow pathways: Sonoma Creek at Lawndale Nathanson Creek at Schell 

CreekInfiltration gallery  (Subbasins as listed for off‐line 

basins)Table 4:

Prioritization

S 3Absence of 

significant water

Step 3No broad water quality concerns in prioritizedsignificant water 

quality concernsprioritizeconcerns in prioritized 

subbasinsAbility to meet supporting objectives

Prioritization

S 3Good potential to address supportingStep 3 address supporting 

objectivesOfba

Hig

dive

Infilgal

Ability to meet 

Supporting Objectives

ff‐line asins

h‐flow 

ersions

tration lleries

Water Quality X X Xsupporting objectives

Water Quality X X XWater Supply X XSystem Sustainability X X XEcosystem X XEcosystem X XAgricultural Land X X XOpen Space  X XCommunity BenefitsCommunity Benefits  X XTable 5:

Prioritization

Step 3Project types LocationsOff‐line basin In lower‐slope, recharge‐suitableOff line basin In lower slope, recharge suitable 

portions of the following subbasins:  Sonoma Creek at Lawndale Sonoma Creek below Dowdall

Creek Nathanson Creek at Schell Creek

High‐flow diversion/  Approximately along existing high‐recharge flow pathways:

Sonoma Creek at Lawndale Nathanson Creek at Schell Creek

Table 6: Infiltration gallery  (Subbasins as listed for off‐line basins)

Prioritization

S 1 S 2 S 3

Absence of i ifi

Low likelihood of i ifi l

Magnitude of 

Step 1 Step 2 Step 3

Ability to meet 

significant water quality concernsprioritize

significant regulatory constraints

potential core benefits

Expected 

Siting feasibility supporting objectives

cost/units of core objective benefit

Short list of potential project concepts (type, location)

Prioritization

prioritize

Short list of potential project concepts (type, location)

Project types LocationsOff‐line basin Sonoma Creek at Lawndale

Sonoma Creek below Dowdall100 – 500 acre‐feet of t Creek

Nathanson Creek at Schell CreekHigh‐flow diversion/  Sonoma Creek at Lawndale

storage

Low‐gradient, high recharge Nathanson Creek at Schell Creek

Infiltration gallery  (Subbasins as listed for off‐line basins)

recharge potential lands

Next StepsNext Steps

We are here

Betty AndrewsPrincipalp

bandrews@esassoc.com

www.sonomacountywater.org