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Drainage Study Sections 30 & 34 for Development of City Wide Stormwater Management Master Plan. Prepared for City of Palm Coast, Florida. Prepared by. March 12, 2013. City of Palm Coast Modeling Priority. Comprehensive Approach for Priority Criteria
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Drainage Study Sections 30 & 34 for Development of City Wide Stormwater Management Master Plan • Prepared for • City of Palm Coast, Florida • Prepared by • March 12, 2013
City of Palm Coast Modeling Priority Comprehensive Approach for Priority Criteria Visual Inspections of Aging Infrastructure Pipe Ratings Historical Records from Rainfall Events Visual Inspections of Stormwater System Public Works High Water Signage Areas Complaints (Service Orders) from Citizens Customer Service Calls Combined With Follow Up Inspections Other Special Situations High Groundwater Areas
City of Palm Coast Modeling Status Section Numbers Sections Already Modeled Next Sections To Be Modeled
Current Study Findings May 2009 Storm Event Rainfall totals range = 20 – 25 inches Rainfall ~ 300 Year – 5 Day storm “R” Section (Section 30) : High water reported at or near homes at 3locations Roadway overtopping reported at approximately 5locations Model confirms storm conditions “E” Section (Section 34) : High water reported at or near homes at 4locations Roadway overtopping reported at approximately 10 locations Model confirms storm conditions
Level of Service Evaluations System Performance Evaluation For Ditches & Canals: Service Level A: Flow is contained within the system (i.e., no flooding of major roadways, minor roadways, yards or buildings occurs) Service Level B: Flow is contained within the right of way (i.e., flooding is limited to the outer lane of major roadways and right-of-way area of yards) Service Level C: Flooding of minor streets precludes travel and flooding of yards is at the buildings but no structure flooding occurs. Service Level D: Extensive flooding of yards including buildings. Note: Level of Service Objective = “B” Level “C” is considered deficient Level “D” is considered unacceptable
Level of Service Evaluations Freeboard System Performance Evaluation For Homes: Home flooding evaluated relative to base flood (i.e., 100-year storm) City has required 1 foot of freeboard above 100-year elevation
Modeling Results Section 30 (“R” Section) High water levels due to: Constrictions between residential areas and primary canal system Low ground or road elevations relative to downstream road elevations or flood stages in Pine Grove Canal 2 homes predicted to flood in a 100-year event Number of homes below City requirement for 100-year event = 19 % 9 Locations with secondary drainage deficiencies for 10 year event Nuisance flooding (2-year event) at 8 road crossings
Deficient secondary roads = 9 Secondary drainage deficiencies Section 30 (“R” Section) – Level of Service
Modeling Results Section 34 (“E” Section) High water levels due to: Constrictions between residential areas and primary canal system Low ground or road elevations relative to downstream road elevations or flood stages in East Hampton Canal No homes are predicted to flood in a 100-year event Number of homes below City requirement for 100-year event = 18 % 4Locations (Nodes) with secondary drainage deficiencies for 10 year event Nuisance flooding (2-year event) at 25road crossings
Secondary drainage deficiencies Section 34 (“E” Section) – Level of Service Deficient secondary roads = 4
Recommended Improvement Plan Section 30 Improvements: Ditch and Pipe Modifications along Seven Locations Cost $360,200 Cost $254,100 $614,300 Section 30 Level of Service Improvements: Homes below 100-year City requirement reduced to 17 % Roadway Deficiencies Eliminated Section 34 Improvements: Ditch and Pipe Modifications Along Two Locations Section 34 Level of Service Improvements: Homes below 100-year City requirement reduced to 16 % Roadway deficiencies eliminated Grand-Total
2012 Program Results “R” Section (Section 31) Improvements - 2012 Ditch and Pipe Modifications (Richardson Drive to Richmond Drive) Construction Cost = $130,530 Engineers Estimate = $215,000
Current & Future Work Current Work in Design Based on Model Section 35 “B” & Section 37 “L” Costs Section 35 Est. Construction Costs $159,700 Section 37 Est. Construction Costs $364,600 Permitting Cost $32,327 Modeling Completed / Design Pending Section 30 Est. Construction Costs $360,200 Section 34 Est. Construction Costs $254,100 Permitting Cost $25,338 Future Work in Design Based on Model Section 31 “R” – Phase 2 Section 31 Phase 2 Est. Construction Costs $733,800 Permitting / Utility coordination Cost $30,000 Sections 35&37 Capital Improvement Est. Construction Costs $3,339,200 Permitting Cost $50,000 Future Model Development Sections 1 & 2“F” & 11 “B” Model Cost $66,235 Permitting Cost $25,000 Grand-Total $5,440,500
Lessons Learned? Section 34 Expectations Continue Maintenance and Selective Improvements City Swale and Ditch Maintenance Has Reduced Future Capital Cost