Department of Biological and Agricultural Engineering. Michael R. Burchell II - Assistant Professor and Extension Specialist

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1 Department of Biological and Agricultural Engineering Hydrologic and wetland ecosystem restoration through rerouting pumped agricultural drainage water: An innovative integrated water management system in Hyde County, NC Michael R. Burchell II - Assistant Professor and Extension Specialist G.M. Chescheir and K.L. Bass Restore America s Estuaries - Galveston, TX November 2010

2 NCSU-BAE as a Partner Department is developing a large research and extension program in ecological engineering, rooted in traditional soil and water conservation Understand and want to achieve sustainability for agricultural facilities Sustainability includes both environmental and ag production goals Environmental projects must be designed to be win-win propositions

3 North River Farms Restoration Plugged drainage ditches Rerouted water with excavation and diversion structures (no pumps higher EL) Water quality improvement/habitat enhancement

4 Hyde County project goals Provide design, construction oversight, and post construction monitoring support to the project team. Design goals include: A system that will significantly reduce drainage outflows to the Pamlico sound without jeopardizing drainage objectives Restore hydrology to surrounding forested wetland areas Allow for re-use of drainage water Improve water quality and habitat in the region Ecotourism potential?

5 Water Management Objectives Reduce pumped drainage water to coastal waters Manage water in impoundments for waterfowl and agricultural benefits Restore natural drainage patterns Restore forested wetlands

6 Design methods Watershed analysis Hydrologic modeling Produce design scenarios include landowner drainage district, and other stakeholder input Implement a phased construction approach (downstream to upstream)

7 Watershed Modeling Methods Estimate current and historical drainage area and flow directions Use the DRAINMOD model to estimate historical and current drainage discharge Estimate the historical and current drainage discharge to Swan Lake Simulate current design scenario and compare drainage to the historical and current situations

8 Farm boundaries and current flow patterns Swan Lake (To Alligator River) Pamlico Sound

9 Estimated Historical Drainage Area Pamlico Sound Historic Flow Directions

10 Farm within Drainage Area Pamlico Sound Current Flow Directions

11 DRAINMOD RAINFALL SURFACE STORAGE (S) INFILTRATION (F) ET RUNOFF (RO) WATER TABLE DRAINAGE (D) DRAIN TUBE OR DITCH DEEP SEEPAGE (DS) RESTRICTIVE LAYER Surface : P = F + S + RO Profile: V n = D + ET - DS - F

12 Land Use Land use effect on outflow Simulated Outflow cm/yr Simulated ET cm/yr Forested Wetland Drained Forest Shrub Wetland Drained Shrub Row Crop (Corn, Soybean) Row Crop (Corn, Wheat, Soy) Green Reservoir (pond in winter) Pond

13 Predicted Annual Outflow to Swan Lake High is 90 th Percentile Low is 10 th Percentile Avg Low High Historical From total drainage area Historical From Lux Farms Current From total drainage area mil m 3 mil m 3 mil m

14 System Design Components Water control structures Pumps Berms/Diversions Impoundments Sloughs Wetland areas Receiving areas (less productive farmland, existing managed forest, existing managed wetlands)

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16 Redirected Flow to Swan Lake Wetland Impoundments Shrub Cropland

17 Predicted Annual Outflow to Swan Lake High is 90 th Percentile Low is 10 th Percentile Avg Low High mil m 3 mil m 3 mil m 3 Historical From total area Historical From Lux Farms Current New Design From Lux Farms New Design From Lux Farms and nearby wetlands Model shows that this design could reduce ALL pumped drainage water from entering the Pamlico Sound in most years

18 Finalizing the design Currently agreement with NCSU, NCCF, and landowner on initial concept design More detailed discussions are needed between all stakeholders (NRCS, drainage district, and USFWs)

19 Construction Methods Phased approach (downstream to upstream strategy) Utilize existing site topography (sloughs, roads, low areas) to minimize excavation costs Minimize disturbance to existing areas that are providing ecosystem services but work to enhance those services (example vegetations planting along sloughs)

20 Conclusions Restablishing Hydrology The new design Could reduce flow from Lux Farms to the sound and river by 100% Would increase flow to Swan lake from 3.3 mil m 3 to 17.5 mil m 3 per year (hydrologic restoration of these areas) Estimated Historical Flow from total drainage area to Swan Lake was 23.8 mil m 3 per year

21 Conclusions This project is a holistic approach towards sustainability of water resources and ecological services Created an integrated water management system Satisfies drainage and irrigation requirements while restoring wetland functions of flood control, habitat, and water quality improvement (estuary) To truly get landowner buy-in to these types of projects, they must satisfy objectives for both parties