lake raleigh wetland creation feasibility study nc state centennial campus melanie carter, jennifer...

Lake Raleigh Wetland CreationFeasibility Study

NC State Centennial CampusMelanie Carter, Jennifer Burdette, Amanda Jones

•Purpose Determine if a wetland could be created in a designated open space on Centennial Campus

•Proposed Project Riverine Wetland Creation -- Groundwater, stormwater, and overbank flow inputs -- Native wetland vegetation -- Wildlife Habitat Pedestrian Greenway and Access

• History

Stormwater pond and proposed wetland location “built” in early 1990’s

Project Description

Existing Conditionso Site Description and Land Useo Physical & Natural Resources

• Soils • Hydrology• Vegetation• Geology• Flood Hazard

o Cultural Resources

Feasibility Study Components

Feasibility Study Components(cont’d)

o Chain-of-Titleo Environmental Hazard Assessmento Jurisdictional Issues

• Waters of the US (Section 404)• Protected Species• Riparian Buffers

o Constraints

Site Description &

Land Use

Existing Site Conditions

• Study Site (~2 acres)

Semi-natural landscape with

planned pedestrian trail

•West Boundary

Perennial Stream and Forebay

• East Boundary

Herbaceous Upland Slope

Existing Site Conditions – Soils

Map Unit Name (Series and Phase): Cecil Clay Loam, 10-20%, Severely Erod. Drainage Class:Well Drained Taxonomy (Subgroup): Typic Hapludult Confirm Mapped Type? Yes No X Profile Description: Depth Matrix Colors Mottle Colors Mottle Texture, Concretions, (inches) Horizon (Munsell Moist) (Munsell Moist) Abundance/Contrast Structure, etc.

0-5 ? 7.5YR 4/6 none n/a silt loam

5-12 ? 7.5YR 4/4 none n/a loam

12-20 ? 10YR 4/4 10YR 4/2 many/prominent sandy loam

Hydric Soil Indicators: Histosol Concretions Histic Epipedon High Organic Content in Surface Layer in Sandy Soils Sulfidic Odor Organic Streaking in Sandy Soils Aquic Moisture Regime Listed On Local Hydric Soils List Reducing Conditions Listed on National Hydric Soils List Gleyed or Low-Chroma Colors Other (Explain in Remarks)

Remarks: No Indicator Met

Existing Site Conditions – Soils Map Unit Name (Series and Phase): Worsham Sandy Loam Drainage Class: Poorly Drained Taxonomy (Subgroup): Typic Ochraquults Confirm Mapped Type? Yes No X Profile Description: Depth Matrix Colors Mottle Colors Mottle Texture, Concretions, (inches) Horizon (Munsell Moist) (Munsell Moist) Abundance/Contrast Structure, etc.

0-7 ? 10YR 4/4 10YR 4/2 many/prominent silty clay loam

7-13 ? 10YR 4/4 10YR 4/2 many/prominent silt loam

13-24 ? 5Y 5/1 none n/a coarse sand

Hydric Soil Indicators: Histosol Concretions Histic Epipedon High Organic Content in Surface Layer in

Sandy Soil Sulfidic Odor Organic Streaking in Sandy Soils Aquic Moisture Regime Listed On Local Hydric Soils List Reducing Conditions Listed on National Hydric Soils List Gleyed or Low-Chroma Colors Other (Explain in Remarks)

Remarks: No Indicator Met

Existing Conditions -- Hydrology

DETAIL

Existing Site Conditions

Jurisdictional Issues

• Area of construction located above ordinary high water mark of perennial stream and does not contain jurisdictional wetlands– No Section 404/401 permit from US Army Corps of Engineers or

NC Division of Water Quality required• Area for proposed wetland creation located within Neuse River Basin

Riparian Buffer– No Neuse River Riparian Buffer Compliance required from NC

Division of Water Quality

ConceptualWetland Design

DETAIL

•Create level area east of stream channel

•Divert ephemeral drainage through constructed wetland

•Build a low levee along perennial channel to detain portion of ephemeral drainage

EphemeralDrainage

Proposed Levee

Area to beLeveled

Conceptual Wetland DesignCross-section

SeasonalHigh WaterTable

Existing Grade

Proposed Grade

PerennialStream

PedestrianTrail

Suggested Wetland Plants

Lizard’s Tail

Swamp Rose

Spicebush

Buttonbush

Jack-in-the-PulpitPhotos courtesy of USDA PLANTS Databasehttp://plants.usda.gov/

• FEMA 100-yr Floodplain Boundary (Red)

• Sewer Line Amendments (Blue)

• Grading Costs (Gray)

• Pedestrian Greenway Access

• Maintenance

Project Constraints