Analette Ochoa, P.E., QSD/P, ToR, WRECO May 22, 2013
Analette Ochoa, P.E., QSD/P, ToR, WRECO
May 22, 2013
LID Treatment Case Study-Bransten Road
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Project DescriptionConceptual Design with Three AlternativesDesign Parameters- MEP vs. C.3 Challenges
Project Description
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Clean Watersheds for a Clean Bay (CW4CB)Industrial SiteLocation chosen to evaluate potential PCB load
reductions977 Bransten Road – “Hot Spot”
Old County Road
Industrial Road
Brans
ten
Road
San Carlos
Treatment BMP Concept
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Both sidesUnderground
treatment/ maximize parking
At hot spots
Considered Three Treatment Alternatives
Treatment BMP Concept – Alternative 1 and 3
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Treatment BMP Concept – Alternative 2
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Treatment BMP Concept
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Alternative 3 chosen for cost-effectiveness
Treatment BMP Concept
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Watershed Map
15.6 ac
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$$ Utilities/PotholingCost effectiveness comparison: $/sq ft of treatmentPublic meetings: Input from property owners
Treatment BMP Concept
Design Parameters
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9 Bioretention Swales in Bulb-outs
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Design Parameters - MEPNeed for parking vs. need for WQ improvementsRoadway watershed vs. off-siteReduced width from 8’ to 6’ to avoid gas line conflictUnderdrain vs. no underdrains18” vs. 12” deep bioretention soilTemporary vs. permanent irrigation
Special Design Parameters
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16” deep curb - stability analysis against overturning or sliding
Impermeable liner -protection of roadway and utilitiesBulb-out Radii -
Consideration for trash/sediment accumulationIndustrial site - Truck turning radius
Irrigation Ordinance - low flow sustainable designPlanting - smaller trees due to utility conflicts
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ChallengesUtility conflicts
Urban AreaWater MainSewerPG&E Gas
Design considerationsImpermeable linerDeeper curb on roadway sideConcerns with differential
settlement
Soils8 boringsHSG DHazardous soilsGroundwater 5.5- 7.5 ft
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Challenges
ChallengesFlat area - Minimum
hydraulic head, no drainage system
Underdrain vs. no underdrain
Planting of trees
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Summary of Bioretention Areas
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Conceptual: 43 parking spaces and 6,920 sq ft of bioretention area, and 3.57 ac (155,700 sq ft) of treatment
Final: 40 parking spaces and 4,540 sq ft of bioretention area, and max 2.61 ac (113,491 sq ft) of treatment
Bransten Road - Lessons Learned
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Coordinate with utility companies earlyInform utilities of project goals (compaction)Obtain schedule for review/comment periodPothole Understanding planting goals with utility clearances
(overhead/underground)
Hold public meetings to get approval from adjacent property owners or companies for parking needs
QUESTIONS
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