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: 1338 Thornhill Dr Project ID Number: 1-3 Problem: Creek bank erosion is occurring along from the northern property line at 1338 Thornhill Drive. The erosion is likely caused by high flows due to an increased amount of runoff upstream. Debris in the stream and invasive species may also be adversely impacting the stream health. In addition, a scour pool is forming at the downstream end of the culvert at 133 Thornhill Dr. This pool stays wet during dry periods and attracts unwanted insects such as mosquitos. Proposed Solution: Stabilize the reach of creek closest to the house by installing bank protection/biostabilization with grade controls on the upstream and downstream ends. Native vegetation should be established at the top of the slope and invasive species should be removed from the entire area. Fill the scour pool with rock to protect the bottom and to encourage positive flow through the area. Required Easements: 133 Thornhill Drive (Temporary Construction Easement) 1338 Thornhill Drive (Temporary Construction Easement) Commentary: Average reach slope is approximately.89% (typical stable slope is. to.7%). Bankfull depth is approximately -feet above channel bed. Bankfull width is approximately 9 feet. The bed armor is dominated by 4-inch diameter gravel. Farther downstream, bank erosion is significant in the entire stretch from the 1338 Thornhill Dr property to the confluence near Mason Grove Lane. However, downstream from 1338 Thornhill, the stream erosion is remote from structures, so active mitigation is unnecessary, other than replacing invasive species with long-rooted native vegetation to improve the riparian corridor. Special care should be made to ensure improvements are not pushing the problem farther downstream. PROJECT SCOPE OF WORK

2 PROJECT INFORMATION SUMMARY CITY OF TOWN AND COUNTRY STORMWATER PROGRAM Project Name: 1338 Thornhill Dr Project ID Number: 1-3 Number of Properties Impacted: Number of Easements Required: Number of Properties Benefited: Opinion of Probable Construction Cost (OPC): Location Benefit Identification (LBI) Project Points: Cost to Benefit Ratio: Coordination Required: x MSD x Corps of Engineers x MO DNR MODOT County Highways City Streets City Parks County Parks x Municipality: City of Town & Country Railroad: x : Utility Service Providers Attached Supplemental Information: x Project Scope of Work x Conceptual Plan Drawing x Itemized Opinion of Probable Construction Cost (OPC) x Location Benefit Identification (LBI) Forms x Existing Condition Photos $6, ,866 Project Source: x Citizen Complaint Municipality Maintenance Government Agency Category of Problem: Description A: Frequent structural flooding from creeks or rivers (floodplain) B: Frequent structural flooding from overland flow (non-floodplain) C: Frequent roadway flooding D: Infrequent structural flooding from creeks or rivers (floodplain) E: Infrequent structural flooding from overland flow (non-floodplain) F: Infrequent roadway flooding G: High risk structural erosion H: High risk roadway erosion x I: Yard erosion J: Moderate risk structural erosion K: Moderate risk roadway erosion L: Erosion or flooding of common ground or unmaintained area M: Yard flooding N: Flooding from inadequate sinkhole O: Flooding from inadequate roadway drainage P: Maintenance of stormwater system facilities Q: Notes: MSD/MO American Water Base Map Number(s): FEMA FIR Map Number(s): P 9189C31K PROJECT INFORMATION SUMMARY

3 OPINION OF PROBABLE CONSTRUCTION COST CITY OF TOWN AND COUNTRY STORMWATER PROGRAM Project Name: 1338 Thornhill Dr Project ID Number: 1-3 ITEM ESTIMATED UNIT EXTENDED NUMBER PAY ITEM DESCRIPTION QUANTITY UNIT PRICE PRICE 1 Mobilization 1 Lump Sum $64.44 $64.44 Bank Protection - Biostabilization 8 Square Yards $6. $4,9. 3 Clearing 1 Lump Sum $,. $,. 4 Excavation Class "B" 9 Cubic Yards $. $49. Excavation Class "C" 49 Cubic Yards $8. $1,37. 6 Grade Control 4 Square Yards $1. $3,6. 7 Rock Blanket 38 Square Yards $8. $3,4. 8 Rock Toe Protection 1 Square Yards $11. $,41. 9 Seeding & Live Staking 6 Square Yards $4. $,9. 1 Sodding - Fescue 6 Square Yards $11. $ Protection and Restoration of Site 1 Lump Sum $, $, SUB-TOTAL - CONSTRUCTION: $4,96.8 Estimated Engineering Fee: $9,. Estimated Geotechnical Engineering Fee: $6,. Estimated Property Survey/Strip Map Preparation Fee: $3,1. Estimated Property Title/Easement Search Report Fee: $8. Estimated Topographic Survey Fee: $1,. Estimated Property Rights Acquisition Document Preparation Fee: $9. Estimated Cost of Easements: $,. Estimated Construction Survey Fee: $. SUB-TOTAL: $48,36.8 3% Contingency: $14,49. TOTAL: $6, OPINION OF PROBABLE CONSTRUCTION COST

4 City of Town & Country Location Benefit Identification Project Name: 1338 Thornhill Dr Project Id Number: 1-3 Location Address / Description: 1338 Thornhill Dr Total Calculated Benefit Points: 1. Evaluation Category Problem Type Benefit Points High Medium Low Public Structure Residential Structure 4 Retaining Wall (Public) Street ROW Improved Channel Retaining Wall (Private) Drainage Structure Yard 3 Unimproved Channel 1 Erosion Erosion Subtotal 8 Flooding Public Structure Residential Structure Impassable Traffic Passable Traffic Accessory Structure Yard Flooding Subtotal Drainage Structure Improved Channel Unimproved Channel 1 Maintenance Street Gutter Swale / Berm Maintenance Subtotal 1 Street Yard 1 Drainage Drainage Subtotal 1 Frequency Rating Degree of Risk >1 / year 1 Life / Limb 1 / year Health 1 / years Property Value.1 1 / 1 years Frequency Rating Multiplier 1 Degree of Risk Multiplier.1

5 City of Town & Country Location Benefit Identification Project Name: 1338 Thornhill Dr Project Id Number: 1-3 Location Address / Description: 1949 Barrett Station Rd Total Calculated Benefit Points:. Evaluation Category Problem Type Benefit Points High Medium Low Public Structure Residential Structure Retaining Wall (Public) Street ROW Improved Channel Retaining Wall (Private) Drainage Structure Yard 3 Erosion Unimproved Channel Erosion Subtotal 3 Flooding Public Structure Residential Structure Impassable Traffic Passable Traffic Accessory Structure Yard Flooding Subtotal Drainage Structure Improved Channel Unimproved Channel 1 Maintenance Street Gutter Swale / Berm Maintenance Subtotal 1 Street Yard 1 Drainage Drainage Subtotal 1 Frequency Rating Degree of Risk >1 / year 1 Life / Limb 1 / year Health 1 / years Property Value.1 1 / 1 years Frequency Rating Multiplier 1 Degree of Risk Multiplier.1

6 1-3 Culvert at 133 Thornhill Drive, looking southwest toward the upstream end. (1) Streambank erosion at upstream location identified at 1338 Thornhill Drive. Since this photo was taken, there is much more vegetation growing on the bank and at the top of the bank. (1) Looking upstream towards the downstream end of culvert at 133 Thornhill Drive. Water flows down steep riffle after leaving culvert. (18) Looking downstream from the same location as previous photo. Water flows from culvert, into fairly steep riffle, and then directly into a bank. The stream then makes a right turn. The pool of water shown here is a concern for the property owner; says it becomes stagnant in dry weather conditions. (18)

7 1-3 Streambank erosion at downstream location identified at 1338 Thornhill Drive. (1) Area is heavily vegetated now; hard to see the channel conditions in summertime. (18)

8 ft Contours P-14D P-16S 7 64 Existing '' U V 1 Project Location184, % Sanitary Manhole " ) Stormwater Inlet, % # * '' 18 V U 141 V U Stormwater Manhole Stormwater Intake/Outfall Stormwater Gravity Main Stormwater Channel Impervious Pavement 18 '' Sanitary Gravity Main Parcels P-146D 48 Proposed 133 Proposed Improvements Strip Map Limits '' Topo Limits DR THORNHI LL P-1S FEMA Flood Hazard Zone Regulatory Floodway 1.% Annual Chance Flood Hazard 8'' P1-3S.% Annual Chance Flood Hazard Easements Required Properties Impacted Properties Benefited Project Benefit Points Conceptual Cost Cost to Benefit Ratio 1338 Problem Description 18'' Stream is eroding and a plunge pool has formed $6,799 41,866 Proposed Solution Description Install grade controls and bank stabilization. Protect creek bottom where pool has formed. P1-S '' Feet 1 inch = 6 feet Warning: If this bar does not measure 1" then drawing is not to scale City of Town & Country Stormwater Program Thornhill Dr