Stormwater Proposal

Proposal for Yestermorrow Design/Build School
Stormwater Feasibility Study
February 1, 2012
Revised February 3, 2012

Prepared by: Watershed Consulting Associates, LLC

Scope of Services

Project Understanding:
Yestermorrow Design/Build School is currently underway with a proposed long-term master planning effort to revitalize the School campus with improved and expanded infrastructure including access, parking, housing, wastewater, and stormwater. Yestermorrow considers water quality improvement a main priority of the revitalization project, and would like to further explore potential options for improved stormwater management on the campus including the daylighting of existing streams, treatment areas for new impervious surfaces, capture and reuse of stormwater for irrigation and a developed permaculture landscape, and creating more of a focus for surface water features through the design and site layout. Currently, one of the main streams that flows through the campus has been culverted. The culvert inlet has been overwhelmed in the past due to high runoff events. In addition, Yestermorrow would like guidance on the applicable permits required for the project and the most efficient and practical way to secure these permits.

To complete the necessary design and permit summary, the following tasks are proposed:

Tasks:

1. Existing Permit and Master Plan Layout Review
Initially, existing plans and permits will be reviewed to gauge the level of detail and usefulness of the information for design, and how the Master Plan layout may fit into the constraints of existing permits. The facility Act 250 Permit, wastewater, and other water quality permits (if applicable) will also be obtained from either Yestermorrow or the Vermont DEC/Act 250 Regional Office and reviewed.
Deliverables: Memorandum summarizing the permit files reviewed and presenting key
information regarding existing permit compliance.

2. Preliminary Hydrologic & Hydraulic (H&H) Runoff Analysis
The current concept Master Plan will be used as a basemap to conduct a preliminary drainage
investigation. It is anticipated that McCain Consulting will provide WCA with the current Master
Plan in DWG format. The current Master Plan layout will be overlaid with current ortho
photography and available Geographic Information System (GIS) data include NRCS-mapped soils, mapped drainage structures under Route 100, topography of the upstream watershed, and mapped surface waters. A site visit will be conducted with a mapping-grade GPS unit (Trimble GeoXH) to locate key features including watershed drainage boundaries, and other site/off site features not currently located on existing surveys or geographic databases. Runoff peak discharges and volumes for a range of design storm events including water quality, 1-year, 10-year, and 100-year, will be predicted using HydroCAD version 10.0 software for existing and proposed conditions to measure the impact of the master plan development project, and also to provide a basis for the conceptual designs as proposed in Task 3. Treatment volumes including the Water Quality Volume (WQv), Groundwater Recharge Volume (Rev), and Chanel Protection Volume (CPv) will also be calculated to provide a basis for conceptual stormwater management feature design.
Deliverables: Existing and proposed condition subwatershed maps, H&H model and treatment
volume summary, GIS shapefiles for existing and proposed landuses.

3. Stormwater Design Alternatives Analysis
A minimum of three concept level designs will be prepared for managing stormwater runoff and
water resources on the project site. Each of these concept designs may include modification to the existing Master Plan layout to accommodate design features and permitting considerations. A decision matrix will be prepared that allows for evaluation of key parameters including level of cost, treatment capabilities, permitting considerations, aesthetics, maintenance, cultural/natural resource impacts, and the feasibility of integrating the construction, monitoring, operation and/or maintenance of the systems into student curricula. The benefits and drawbacks of each option will be discussed with Yestermorrow staff at a project meeting onsite. For the preferred option as agreed upon with Yestermorrow, a more comprehensive and polished concept plan will be prepared for submittal to the Town of Waitsfield.
Deliverables: Three (3) concept level Site Plans including proposed grading, treatment system
design, and development layout in PDF and DWG formats. Decision matrix and discussion of
the options analyzed at an onsite meeting with project team members. One (1) final concept
Site Plan for the preferred option in PDF and DWG formats, and a full size (24”x36”) hardcopy
if requested.

4. Final Summary Report
A final narrative summary will be prepared outlining methodologies and discussing the options
evaluated and the justification for the recommended design option. A discussion of the applicable
permitting considerations, including timing and sequence of applying for various authorizations will also be included in the final report.
Deliverables: Final summary report in PDF format, hardcopy if requested.

Proposed Timeline:
WCA is available immediately following execution of a contract in February to initiate the desktop analysis and conduct a site visit. It is anticipated that WCA could have a decision matrix and discussion of alternatives completed by March 9th, 2012 for input from Yestermorrow. Recommended option plans and a final summary report will be provided by March 23th, 2012.