Plan of Work

Pitt County officials will develop a watershed management plan for upper Swift Creek and Fork Swamp (a total area of approximately 45 square miles).

Goals & Challenges

The primary goals of the watershed plan will be management of stormwater runoff from existing developed areas and floodplain management through strategic conservation easements and selective enhancement. The challenge is to improve water quality in an area with a channelized stream network. The project approach includes six tasks.

Task 1. Subwatershed Characterization

  • Gather existing information on land use (GIS), stormwater conveyance (GIS and database for Winterville and Ayden), state and local regulations, projected future growth, water quality, and floodprone areas.
  • It is assumed that no new stormwater conveyance mapping will be done. (What about areas that have not been mapped? Greenville)
  • Divide project area into approximately 10 to 12 subwatersheds and characterize each based on existing information. Scrutinize the results to identify problem areas and areas worthy of protection.
  • This task will help to establish the needs for each subwatershed in terms of this project and future management issues.

Task 2. Conduct Benthic Macroinvertebrate Monitoring

  • Conduct benthic macroinvertebrate monitoring at selected subwatershed sites for the purpose of characterizing long-term water quality and instream habitat.
  • Seek NC Division of Water Quality’s assistance and contract experienced biologists to sample the benthic macroinvertebrate communities and interpret the results. This work would include a habitat assessment following EPA’s Rapid Bioassessment Protocol. This benthic monitoring task would determine if the aquatic life designated use is impaired, and, if so, the potential causes of the impairment(s).

Task 3. Target Riparian Protection & Stream Enhancement

  • Building on information from Task 1, through a combination of GIS analysis and field visits, identify sites that provide water quality benefits and flood water storage and target them for conservation.
  • GIS analysis will identify large parcels adjacent to streams with flood problems. Contact landowners of most promising parcels to obtain permission to field verify these sites.
  • For stream enhancement, identify stream reaches that could be enhanced by creating floodplain benches and planting them with native riparian vegetation. Obtain landowner permission to survey 10 sites. The surveys will include measurement of at least two channel cross sections per reach.
  • Baker Engineering will conduct analysis of bankfull dimensions to determine the appropriate elevation of a floodplain bench and if a suitable one is present. If one is not, an enhanced channel cross section will be recommended.
  • Grade control to prevent channel incision will also be targeted where it would be beneficial. Adding stream pattern (e.g., meander bends) will not be targeted but if site constraints allow, its viability may be considered.
  • The project will work with the Pitt County Drainage Districts on this task so that the enhancement and conservation measures do not conflict with the districts’ maintenance efforts.

Task 4. BMP Site Identification & Prioritization

  • Through a combination of GIS analysis and field visits, identify up to 30 sites as candidates for stormwater BMP sites and identify the type(s) of BMP appropriate for each location.
  • Target areas within the three municipalities or those with urbanizing land.
  • Innovative stormwater BMPs that use infiltration (e.g., bioretention areas) and natural filtering processes (e.g., constructed wetlands) will be preferred. The potential for constructing detention basins will be explored with the regulatory agencies.
  • Estimate pollutant loads with and without a BMP at each potential site using basic modeling techniques (e.g., Schueler’s Simple Method).
  • Evaluate each candidate BMP for probable effectiveness, initial and ongoing costs, and construction feasibility. Develop a potential BMP database to archive the results.
  • Rank the candidate BMPs in terms of desirability for implementation.

Task 5. Educational Workshops

  • Annual or bi-annual workshops will be held to educate local officials and the public about the project and stormwater management.
  • This task will provide matching funds through in-kind services.
  • Teach the public attendees how they can improve water quality and flooding. Examples include pollution prevention measures and homeowner stormwater management, including construction of bioretention areas and use of cisterns.
  • Seek to build support for BMP and conservation/enhancement sites.
  • Partner with East Carolina University and Pitt Community College on this task and possibly others.
  • Baker Engineering will prepare and deliver a PowerPoint presentation on the comprehensive watershed plan (this project) at one of the workshops.

Task 6. Publish Report - Upper Swift Creek & Fork Swamp Watershed Action & Strategic Plan

  • Baker Engineering will produce a plan document that will include GIS figures, results tables, and text.
  • Detailed observations from existing data in Task 1. Will include analyses of designated subwatersheds.
  • Summary of process and areas targeted for conservation in Task 3.
  • Summary of process and areas targeted for enhancement in Task 3.
  • Summary of BMP needs and opportunities identified in Task 4.
  • Specific recommendations for improving the stormwater water conveyance systems
  • Provide ten hard copies and a digital copy of the report.
Work on this plan is scheduled to begin in Spring 2009 with the anticipated completion date of Spring 2011.