Laserfiche WebLink
Drainage and Stormwater Costs <br /> Three options relative to managing storm water drainage on the site were explored. Following <br /> are the options and their costs and assumptions. <br /> Option#1• Johanna Marsh Bio-Filtration Basin <br /> - Street storm sewer system and inlet capacity increased. <br /> - Bio-Filtration feasible in upland Johanna Marsh Area. <br /> - Resident buy-in to residential boulevard basins. <br /> Estimated Cost: $320,000 to $400,000 (depending on pavement rehabilitation) <br /> Advantages: Most treatment conducted in a single area. <br /> Opportunity to fix erosion and gully problem. <br /> Residents participate in storm water treatment and maintenance. <br /> Meets RCWD volume control requirement. <br /> Disadvantages: Possible groundwater issue. <br /> Significant tree loss or loss of tennis court <br /> Option#2• Johanna Marsh Constructed Wetland Improvement <br /> - Street storm sewer system and inlet capacity increased. <br /> - Constructed wetland allowed in Johanna Marsh area. <br /> - Resident buy-in to residential boulevard basins. <br /> Estimated Cost: $350,000 to $430,000 (depending on pavement rehabilitation) <br /> Advantages: Most treatment conducted in a single area. <br /> Opportunity to fix erosion and gully problem. <br /> Residents participate in storm water treatment and maintenance. <br /> Disadvantages: Option may be discouraged — has to prove that the function and value of <br /> the wetland is not compromised after the project has been conducted. <br /> Alternative compliance sequencing needed in order to proceed. <br /> Flood plain may limit viability <br /> Option#3' No Improvement to Johanna Marsh <br /> - Street storm sewer system and inlet capacity increased. <br /> - No treatment basin constructed in Johanna Marsh. <br /> - All treatment accomplished in filtration trenches in boulevards. <br /> - Residents have optional plantings of basins. <br /> Estimated Cost: $380,000 to $430,000 (depending on pavement rehabilitation) <br /> 11 <br />