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Similar to Determining Volume Sensitive Tidal Creeks Beaufort County
Similar to Determining Volume Sensitive Tidal Creeks Beaufort County (20)
Determining Volume Sensitive Tidal Creeks Beaufort County
- 1. Determining Volume Sensitive Waters in Beaufort County, SC Tidal Creeks Kevin Pitts Denise Sanger, John Leffler, Jeff Brunson, George Riekerk, Robert O’Quinn IV, Eric Montie, Anne Blair, April Turner
- 2. • Beaufort County has experienced extensive development and has a high level of environmental consciousness. • Alarmed over impaired waters and negative consequences of stormwater runoff into their estuaries. • Stormwater Standards based on volume control satisfy most bacteria and pollutant requirements.
- 3. • Beaufort County approached SCDNR for assistance in identifying its tidal watersheds that are most sensitive to stormwater runoff. • “Priority Critical Waters” • Areas that might require more stringent volume control ordinances, or county engineered stormwater control retrofits
- 4. Memorandum of Understanding • Outlines a 5-year partnership • Studying the relationship between rainfall events and stormwater-induced changes in salinity within the waters of County-identified priority watersheds
- 5. Additional Funding Opportunity • National Estuarine Research Reserve (NERR) System’s Science Collaborative Grants Program • Expand effort to five watersheds simultaneously. • Generate data and interpretations from 5 sites in 1-2 years rather than 1 site per year over 5 years. • Incorporate information into the County’s 2016-2026 Stormwater Management Plan.
- 6. Partners • Beaufort County (E. Larsen, D. Polk) • South Carolina Department of Natural Resources (D. Sanger, J. Leffler, G. Riekerk, J. Brunson, K. Pitts, R. O’Quinn IV) • University of South Carolina – Beaufort (E. Montie) • NOAA – Hollings Marine Laboratory (A. Blair) • South Carolina Sea Grant (A. Turner)
- 7. 1. Inform & seek advice from the Natural Resources Committee of County Council and the Stormwater Management Utility Board. 2. Work closely with a Watershed Advisory Committee that advises and assists. 3. Communicate research activities and results to a wider community. Primary Collaborative Objectives
- 8. Watershed Advisory Committee Provide advice and assistance in: – watershed selection – specific deployment sites – interpretation of results – site-specific modeling modifications – synthesis of results – translation of results for government policy makers Third workshop First Workshop Second workshop
- 9. Primary Research Objectives 1. Identify which watersheds are most volume sensitive. 2. Delineate the spatial extent of stormwater impact on major tidal waters. 3. Project impacts on volume control of – engineered retrofits – changing weather patterns
- 10. • Monitor 5 systems over 9-10 month period. • Install a data-logging rain gauge in each watershed. Methodology • Deploy 6-9 data-logging instruments in each watershed to measure salinity and tidal cycle.
- 11. • Evaluate magnitude of salinity change as function of rainfall. • Determine extent of signal downstream attenuation. • Model the runoff volume and compare to observed data. • Identify location of “critical volume-sensitive waters”. Methodology
- 13. Example of Okatie Data Tidal phase Salinity at the Hwy 278 bridge Salinity at the Old Field station Rainfall
- 14. Okatie – Sampling Sites
- 15. Okatie – Watershed # 1
- 16. Okatie – Watershed # 2
- 17. Okatie – Watershed # 3
- 18. Okatie – Watershed # 4
- 19. Okatie – Watershed # 5
- 20. Okatie – Watershed # 6
- 21. Okatie – Watershed # 5
- 22. Okatie – Watershed # 4
- 23. Okatie Watersheds Rainfall - 3.38 in Okatie-1st Watershed Rainfall - 3.38 in OkatieMonitoringSites & Watershed#1(278Bridge) Stormwater Runoff Modeling System Model based on modified USDA-NRCS methods Calculates runoff based on environmental settings (soil types, impervious surfaces, watershed size, topography) Projects effects of development, stormwater management retrofits, and climate change scenarios.
- 24. Project Significance Directly supports a local government that values its natural resources and is seeking scientifically credible data to supports its efforts to protect those resources.
- 25. Project Significance Improves the state’s understanding of the extent to which stormwater runoff impacts estuarine bodies of water. This knowledge may be used to increase the resilience of coastal communities.
- 26. Project Significance Provides SCDNR with information essential for managing tidal waters that are nursery areas for important finfish, shrimp, crabs, and shellfish.
- 27. Acknowledgements • National Estuarine Research Reserves Science Collaborative Program • ACE Basin National Estuarine Research Reserve • Beaufort County, South Carolina • South Carolina Sea Grant Consortium • University of South Carolina – Beaufort • The Volunteers of the Watershed Advisory Committee • The Staff of the Waddell Mariculture Center • The Staff of the Ecosystem Section of SCDNRs’ Marine Resources Research Institute Questions?
Editor's Notes
- Hi. My name is Kevin Pitts. I’m based at the Waddell Mariculture Center and I’m a member of the new Ecosystem Section with-in the Marine Resources Research Institute. I’d like to tell you about a project we have been working on with a variety of partners.
- Beaufort County is an area that has experienced extensive new development over the last 30 years. It is a progressive county that recognizes that much of its quality of life depends upon the health of its estuaries, which account for approximately half of the county’s surface area. Some of these estuarine systems have been declared impaired by DHEC. Beaufort County has enacted some of the toughest stormwater management ordinances in the nation. The County’s approach is based on volume control requirements, the rationale being that by controlling volume discharge levels, other pollutants such as bacteria and chemicals will also be controlled.
- In 2012 Beaufort County approached us to help them identify those tidal watersheds that are most sensitive to stormwater runoff. These would be designated as “Critical Waters” and the County would give them priority consideration. Possible actions might be to engineer retrofits for existing stormwater retention structures, or even perhaps to enact more stringent regulations for reducing stormwater runoff in those watersheds.
- SCDNR then entered into a Memorandum of Understanding with the County that outlined a 5-year partnership for studying the relationship between rainfall events and stormwater-induced changes in salinity within the waters of County-identified priority watersheds. The plan agreed to focus on salinity changes since this would be easy to monitor and most indicative of the volume influx of fresh water.
- With this 5-year Agreement in hand, we had an opportunity for additional funding through the National Estuarine Research Reserves’ Science Collaborative Program. This allowed us to expand our efforts to all 5 watersheds simultaneously over a 1 -2 year period instead of 1 site per year. This means that the results of the study will be available in time for incorporation into the County’s new 10-year stormwater management plan.
- These are the partners involved with both the Memorandum of Understanding and the Science Collaborative funded project. - Beaufort County is the government entity seeking to manage stormwater, DNR and USCB are conducting the primary research, Sea Grant is providing collaboration and communication expertise, and the Hollings Lab is involved with predictive modeling of the collected data.
- This project is truly a collaborative effort the Project Staff is interfacing significantly with three primary groups of intended users. the Natural Resources Committee of County Council and the Stormwater Management Utility Board, a Watershed Advisory Committee composed of professional stormwater managers and lay volunteers with stormwater management experience, And the general public through several community oriented non-governmental organizations.
- Three workshops where planned with the Watershed Advisory Committee. The Committee is significantly involved in directing this project, from selecting the watersheds for study, to interpreting the data collected, to presenting the resultant conclusions to government bodies and ensuring their incorporation into decision-making.
- The research plan is to assess the relationship between rainfall and salinity change throughout the length of specific tidal creeks. This will enable us to rank different watersheds in terms of their response to stormwater runoff, and to determine how far downstream such effects are measureable. The modeling effort will help us to predict the impacts that County-engineered stormwater management retrofits might have. And also, help the County plan for more extreme precipitation events predicted in the future.
- The Project Team is monitoring 5 watersheds simultaneously and long enough to capture a variety of precipitation events. A continuously recording rain gauge is installed in each watershed. As well as six to nine continuously recording instruments that measure salinity and tidal cycles. They are deployed in an array downstream from the headwaters of the creek.
- With the data collected by these instruments, we can evaluate the magnitude of the salinity change in the creek due to stormwater runoff, and the distance downstream that this freshet’s effect can be detected. This information is combined with a model of that particular watershed. The results will be used to rate the sensitivity of each watershed to stormwater runoff, and will help the County establish priorities regarding “critical volume-sensitive waters”.
- The five watersheds being monitored were selected by the County and the Watershed Advisory Committee. They are the Okatie River, the May River, Battery Creek, Wallace Creek. Huspah Creek will come on-line soon.
- This graphic is an example of the salinity ranges on the Okatie at the most upstream station (Hwy 278 bridge) in blue and the most downstream site (Old Field) in green. The tidal range is shown at the bottom in purple. Rainfall events ininches are indicated at the top. The first three cycles follow a dry period of about 1-2 weeks. Look at the Hwy 278 bridge site. The salinity range (lows to highs) increases after 0.55 inch of rain and continues to show wide fluctuations throughout the rest of the graph. also with each additional rainfall event the maximum salinity decreases and starts to recover before decreasing again from the 0.88 inch rainfall. At the Old Field site, the location furthest downstream. the salinity does not fluctuate as much This is the expected pattern. But you can still see an increase in the salinity range and lowering of the maximum and minimum values. In particular, the fluctuations increase with the increased amount of rainfall.
- As an example, each of the dots represents one of the salinity/tidal monitoring stations in the Okatie River, starting from the headwaters and going downstream to an area that we think the tidal exchange will cause it to no longer be stormwater volume-sensitive.
- Each station is measuring waters impacted by watersheds of increasing sizes.
- Although the watershed size increases, the influence of tidal exchange in wider and deeper channels eventually attenuates the stormwater signal such that waters beyond that point are no longer volume sensitive.
- For example, suppose the stormwater signal is no longer detected at the last two stations….
- Station four is the last station where an impact can be measured. This then identifies the extent of the watershed that delineates “sensitive waters” or “critical waters” within that system.
- Anne Blair with the National Oceanic and Atmospheric Administration’s Hollings Marine Laboratory in Charleston is using the Stormwater Runoff Modeling approach that she developed to improve interpretation of the data we collect. Her approach modifies the widely used USDA Natural Resources Conservation Service runoff model specifically for the soils and topography of the Lowcountry and incorporates the amount of impervious surface. We will use her model to predict the impacts of possible stormwater management retrofits, as well as the implications of changes in weather patterns due to projected climate change scenarios.
- This project is a great example of how a variety of academic and local, state, and federal agencies can work together to address a major coastal problem that is the result of the widespread, rapid development in the coastal zone. SCDNR is providing unbiased, credible scientific expertise to directly assist a progressive local government in making informed decisions to protect its estuarine natural resources.
- Estuarine systems are extremely complex and dynamic for a variety of reasons. This work will improve our understanding of the extent to which stormwater may impact estuarine waters. Coastal communities may be able to use this information to increase their resilience in the face of major stressors such as increasing, rapid development and predicted changing climate scenarios.
- This understanding of the extent to which development-induced stormwater runoff impacts our estuaries will be important to incorporate into SCDNR’s management of our tidal waters, …. which of course are essential nurseries for a variety of recreationally and commercially important finfish, shrimp, crabs, and shellfish.
- Thank you for your attention. May I answer any questions?