Workshop #1 8:30 am – 12 pm (BACK)
Wednesday, October 30
Establishing Stormwater Discharge Thresholds for Watershed-based Planning Analysis
Dr. Pamela C. Dodds, Registered Professional Geologist
Laurel Mountain Preservation Association
Materials that students need to bring: Students are invited to bring a laptop to transfer the instructional presentation and notes via a flash drive.
Materials student will receive: Students will receive handouts of topographic maps, equations for determining discharge, and charts used in determining hydrologic parameters
At the completion of this workshop students will be able to:
1. Use the global water balance to understand the finite amount of water resources on continents.
2. Delineate a watershed using a topographic map.
3. Determine the acreage within a watershed and within portions of a watershed.
4. Calculate stormwater discharge using the Rational Method (Q = CiA), including appropriate selection of parameters for runoff coefficients for various ground covers and rainfall intensity, using standard charts.
5. Determine a threshold for stormwater discharge to control development within a watershed.
6. Determine methods for reducing negative impacts of excessive stormwater discharge.
The introductory presentation will provide global water balance quantifications to explain and emphasize the finite amount of water available on continents. Increased stormwater discharge can offset the existing balance, reducing the availability of water resources on our continents. Increased stormwater discharge also causes downstream erosion of stream banks, with the result of increased downstream sedimentation. The workshop will provide the skills necessary to delineate watersheds on topographic maps and determine watershed and sub-watershed acreages in order to calculate stormwater discharges, using the Rational Method, on various ground covers within a watershed. As stated by the EPA, a 10 percent impervious cover can create negative impacts to a watershed. The workshop will provide instruction for determining stormwater discharge for a 10 percent impervious cover within a watershed to use as a threshold for development of various ground covers within that watershed. Additionally, methods will be presented for use in reducing stormwater discharge within watersheds. The stormwater discharge calculations serve as a planning tool to control development within a watershed in order to preserve our water resources. The methodologies presented for reducing stormwater discharge provide a means for maintaining groundwater recharge and for reducing stream bank erosion downstream.