PROJECT SCOPE OF WORK CITY OF TOWN AND COUNTRY STORMWATER PROGRAM

Transcription

1 PROJECT SCOPE OF WORK CITY OF TOWN AND COUNTRY STORMWATER PROGRAM Project Name: Essex Point Subdivision/Sellenriek Retention Project ID Number: 2-A Problem: The watershed above the Essex Point Subdivision is approximately 72 acres. It includes portions of the Village of Country Life Acres, several subdivisions, and the undeveloped property owned by the McDonnell Family. Regulations administered by the Metropolitan St. Louis Sewer District at the time of development did not address the water generated upstream of and then flowing through the subdivision and its stormwater facilities. The peak water flows generated by these areas during and following large rain events are causing erosion and potential flooding in the area of Sellenriek Road and Delvin Drive. In addition, debris and sediment from upstream create a maintenance problem the Essex Point Subdivision retention basin. Proposed Solution: This project includes dredging the existing Essex Point Subdivision retention basin and constructing a wetland. Description of Proposed Alignment: Dredge the downstream part of the existing retention basin of the Essex Point Subdivision and construct a forebay and a wetland to provide water quality treatment at the upstream part of the basin with the dredged material. Required Easements: Delvin Court (Temporary Construction Easement) 9 Delvin Drive (Temporary Construction Easement) 927 Delvin Drive (Temporary Construction Easement) 92 Delvin Drive (Temporary Construction Easement) Commentary: Depending on MSD and other regulatory authorities, extensive testing of the material to be dredged may be required. Further evaluation during design will dictate the most effective improvements. PROJECT SCOPE OF WORK

2 PROJECT INFORMATION SUMMARY CITY OF TOWN AND COUNTRY STORMWATER PROGRAM Project Name: Essex Point Subdivision / Sellenriek Retention Project ID Number: 2-A Number of Properties Impacted: Number of Easements Required: Project Source: x Citizen Complaint Number of Properties Benefited: 2 Municipality Opinion of Probable Maintenance Construction Cost (OPC): $38,687.2 Government Agency Location Benefit Identification (LBI) Project Points:. Category of Problem: Description Cost to Benefit Ratio: 7,62 A: Frequent structural flooding from creeks or rivers (floodplain) B: Frequent structural flooding from overland flow (non-floodplain) Coordination Required: C: Frequent roadway flooding x MSD D: Infrequent structural flooding from creeks or rivers (floodplain) x Corps of Engineers E: Infrequent structural flooding from overland flow (non-floodplain) x MO DNR F: Infrequent roadway flooding MODOT G: High risk structural erosion County Highways H: High risk roadway erosion City Streets I: Yard erosion City Parks J: Moderate risk structural erosion County Parks K: Moderate risk roadway erosion x Municipality: City of Town & Country L: Erosion or flooding of common ground or unmaintained area Railroad: M: Yard flooding x : Local Utility Service Providers N: Flooding from inadequate sinkhole O: Flooding from inadequate roadway drainage Attached Supplemental Information: x P: Maintenance of stormwater system facilities x Project Scope of Work Q: x Conceptual Plan Drawing x Itemized Opinion of Probable Construction Cost (OPC) x Location Benefit Identification (LBI) Forms x Existing Condition Photos Notes: MSD/MO American Water Base Map Number(s): FEMA FIR Map Number(s): 2P 2989CO6H PROJECT INFORMATION SUMMARY

3 OPINION OF PROBABLE CONSTRUCTION COST CITY OF TOWN AND COUNTRY STORMWATER PROGRAM Project Name: Essex Point Subdivision / Sellenriek Retention Project ID Number: 2-A ITEM ESTIMATED UNIT EXTENDED NUMBER PAY ITEM DESCRIPTION QUANTITY UNIT PRICE PRICE Mobilization Lump Sum $9, $9, Placement of Sediment,8 Cubic Yards $3.7 $9,8. 3 Excavation of Sediment,889 Cubic Yards $8. $87,. Excess Sediment Disposal,7 Cubic Yards $.2 $3,9.68 Dewatering Lump Sum $,. $,. 6 Protection and Restoration of Site Lump Sum $2,337.8 $2,337.8 SUB-TOTAL - CONSTRUCTION: $22,282.9 Estimated Engineering Fee: $,. Estimated Geotechnical Engineering Fee: $,. Estimated Property Survey/Strip Map Preparation Fee: $2,. Estimated Property Title/Easement Search Report Fee: $,6. Estimated Topographic Survey Fee: $8,. Estimated Property Rights Acquisition Document Preparation Fee: $,8. Estimated Cost of Easements: $,. Estimated Construction Survey Fee: $. SUB-TOTAL: $296, % Contingency: $89,.7 TOTAL: $38,687.2 OPINION OF PROBABLE CONSTRUCTION COST

4 City of Town & Country Location Benefit Identification Project Name: Essex Point Subdivision / Sellenriek Retention Project Id Number: 2-A Location Address / Description: Essex Point Subdivision Retention Basin Total Calculated Benefit Points: 2.6 Evaluation Category Problem Type Benefit Points High Medium Low Erosion Residential Structure Retaining Wall (Public) Street ROW Improved Channel Retaining Wall (Private) Drainage Structure Yard Unimproved Channel Erosion Subtotal Residential Structure Impassable Traffic Passable Traffic Accessory Structure Yard Flooding Flooding Subtotal Drainage Structure 6 Improved Channel Unimproved Channel Street Gutter Swale / Berm (Retention Basin) 8 Maintenance Maintenance Subtotal 2 Street Yard Drainage Drainage Subtotal Frequency Rating Degree of Risk > / year Life / Limb / year Health / years Property Value. / years Frequency Rating Multiplier Degree of Risk Multiplier.

5 City of Town & Country Location Benefit Identification Project Name: Essex Point Subdivision / Sellenriek Retention Project Id Number: 2-A Location Address / Description: Project 2-7 Total Calculated Benefit Points: 2. Evaluation Category Problem Type Benefit Points High Medium Low Residential Structure Retaining Wall (Public) Street ROW Improved Channel 9 Retaining Wall (Private) Drainage Structure Yard 3 Unimproved Channel (Fence) 6 Erosion Erosion Subtotal 9 Residential Structure Impassable Traffic Passable Traffic Accessory Structure Yard Flooding Flooding Subtotal Drainage Structure Improved Channel Unimproved Channel Maintenance Street Gutter Swale / Berm Maintenance Subtotal Drainage Street Yard Drainage Subtotal Frequency Rating Degree of Risk > / year Life / Limb / year Health / years Property Value. / years Frequency Rating Multiplier Degree of Risk Multiplier.

6 2-A Looking southwest at incoming pipes to the Essex Point Subdivision retention basin. (27) Looking north at the Essex Point Subdivision retention basin. (27)

7 89 2O-6S 2O-97S 2 2O-67S 8 2O-93S 2O-D 2O-9D 2O-7D 2O-6D 96 2O-7S 938 2O-2D 2O-69S Sediment deposition in retention basin. Proposed Solution Description Dredge the retention basin to original elevation and construct a wetland with dredged material O-67D 9 8' ' O-73S 29 Feet inch = feet Warning: If this bar does not measure " then drawing is not to scale City of Town & Country Stormwater Program 2O-2D 2O-D 2. $38,687 7,62 Problem Description 2O-2D SELLENRIEK RD 6 6 DELVIN DR Easements Required Properties Impacted Properties Benefited Project Benefit Points Conceptual Cost Cost to Benefit Ratio % Annual Chance Flood Hazard % Annual Chance Flood Hazard Regulatory Floodway 2O-9S 29 FEMA Flood Hazard Zone Proposed Improvements 2O-S Proposed 2O-3D 2O-D Stormwater Gravity Main Parcels 6 2O-9S 2O-96S 9 Stormwater Intake/Outfall Topo Limits 92 CT O-D DELVIN 2O-8S Stormwater Manhole Strip Map Limits 2O-22D 8 2O-S Stormwater Inlet Pavement 2O-9D 2O-68D 2O-99S 2O-98S O-7D 2O-8D 9 2O-S 2O-23D " ) Sanitary Gravity Main Impervious 9 8 Sanitary Manhole Stormwater Channel V U -ft Contours, % # * 2O-2D Existing, % 2O-D 973 2O-66S 2O-D V U 7 6 2O-6S O-3D U V Project Location Essex Point Subdivision / Sellenriek Retention 2-A