Bill Kirby Smith
1996 - 2004
The objective of this multi-agency, multi-disciplinary project is
to 1) quantify the effects of land use change on shellfish closures
and 2) assess techniques that can be used mitigate those impacts. This
report is based on preliminary analyses conducted over the last 18 months.
The project focuses on the 800-acre watershed in Carteret County, NC that
is the drainage for Jump Run Creek. Bacterial data from 1970 through 1998
indicate little change in overall loading since 1974, which is when closure
management began. Recent grab sample data from the tributaries indicate
high levels of bacteria during storm events and moderate levels during dry
weather. The majority of the loading is coming from the portion of the watershed
draining an older, medium density neighborhood (single-family houses) and
a trailer park. A door-to-door survey found two malfunctioning septic systems,
more than 100 pets, and the presence of wildlife. Change analysis of land
use/land cover shows hydrologic modifications were instituted in the 1970's.
Dye studies confirm that water moves through the watershed in hours indicating
that time for bacterial mortality is limited. Future analyses include ground
water sampling, automated storm water monitoring, and DNA tracking of fecal
sources. Planned mitigation practices will include riparian buffer restoration,
stormwater wetland, bio-retention, peat filters, and education. Locations
and sizing of practices will be determined through GIS-based hydrologic
analysis of the watershed in conjunction with a community-design/ educational
approach involving neighborhood citizens.
Community Design Workshop
A Community design workshop was held successfully on Saturday, September 11th, 1999. The workshop was generously hosted by the Carteret-Craven Electric Co-operative, and started at 10:30AM and ended around 12:30PM. Ten residents of the water shed attended.
Everyone met in the main meeting room of the Electric Co-operative in-between ten and ten thirty the morning of the eleventh. The workshop started with coffee and donuts. Participants were asked to sign in and identify where they lived with pushpins on a 32" by 40" map of the watershed. The rational behind this was to get people familiar with the map they would be using later to do analysis and suggest the placement of Best Management Practices or BMP's and to identify area of the watershed the participants lived in. All ten participants identified the neighborhood below Highway 24 as their home. A topographical model of the watershed, and aerial photography of the watershed were displayed.
Barbara Doll, NC Sea Grant, presented a twenty minute slide show that explained the efforts of researchers in the Jumping Run creek watershed. Doll explained the Best Management Practices (BMP's) that could apply to the area. The BMP's included grassy swales, permeable pavement, constructed wetlands, and rain gardens. Posters with text and pictures of the BMP's were at the front of the room.
About 11:15AM the group informally broke into two groups to look at maps of the watershed, which had been prepared by Michael Holmes. The maps showed the roads, houses, the land and water masses, and ditches in the watershed. Participants gathered around these maps to share their first hand experiences. They first identified their homes. The second topic was general areas where flooding occurred. There were many complaints about the ditches on the roads not working correctly and yards flooding. Many of the participants have family that lives in their neighborhood. After finishing with their own homes they would talk about their families' homes and yards. Some people volunteered their areas that flood for wetlands area. One participant volunteered her daughter's yard, "since water gathers there away." Generally the emphasis for the home owners was to get the water off their property more efficiently. Notes and drawing were made on the maps.
The Workshop generated a list of land owners willing to host BMPs on their properties, and potential BPM sites to investigate.
Land Use Change Analysis
Jumping Run Creek in North Carolina is the focus of a multi-disciplinary, multi-agency, watershed - based project that combines in-column water quality data, stormwater monitoring, stream flow measurements, with watershed assessment techniques, and community involvement to investigate causes of and solutions to reduce bacterial loading to shellfish beds. Field data indicate that stormwater flows are the primary transport vector; however, total "impervious surface" area in the water
shed, a popular indicator of stormwater threats to water quality, is lass that 5%. This is well below the threshold of 12% -25% cited as the level which cause water quality degradation. Very little is understood with regards to the effects of land use change and bacterial loading. This effort reports on approach to measure change to land cover and relate it to bacterial loading rates.
Current parcel data was overlain onto scanned images of aerial photos of the watershed ranging from 1967 to 1994. Classification ranks were assigned to each parcel indicating the degree of land use / cover change for three categories -- clearing, ditching, and impervious surface area. These data were organized in a GIS database to facilitate spatial as well as temporal analysis. Using correlation and regression techniques, the variables were analyzed against thirty years of bacterial data.
Increased ditching in the watershed was positively correlated and statistically significant with increased bacterial loading. Imperviousness and cleared areas were not good indicators of bacterial densities. These results imply that time of concentration of rainfall in the watershed is an important factor in delivery of viable bacterial loads to shellfish resources in the sound.
| The objective of water quality monitoring in the Jumping Run watershed
is to document nitrogen, phosphorus, sediment, and bacterial loading
from areas of the watershed. Documenting these loads prior to the
implementation of mitigating practices (i.e. BMPs) helps identify
where the practices are most needed while continuing the monitoring
after the implementation of the BMPs help determine the effectiveness
of the practices.
Monitoring involves measuring and sampling the discharge on the
two main tributaries to and one site on the main stem of Jumping
Run. The tributary sites were selected picked because the watershed
draining to the sites contained different land uses (industrial
vs residential) and they were the two main tributaries to Jumping
Run. The monitoring site on the mainstem was chosen because it was
as close to Boque Sound as possible without being significantly
affected by tides. Flow-weighted samples of storm event discharge
and grab samples of baseflow from each site are collected and analyzed
for suspended solids, ammonia, nitrate, dissolved phosphorus, turbidity,
conductivity, and pH.
Best Management Practices
These sites are under construction 8.21.2000
Carteret-Craven Electric Co-operative
Clean Water Management Trust Fund
Duke Marine Lab
NC Cooperative Extension Service
NC Department of Water Quality, Non Point Source 319 Program
NC Department of Water Quality, Wetland Restoration Program
NC Division of Environmental Health, Shellfish Sanitation Branch
NC State University
NC Sea Grant
The community in the Jumping Run watershed.
Stormwater Management for homeowners
Stormwater Structural BMP's
NC State University Design Extension Program