Rebecca Schneider, Nancy Trautmann, & Linda Wagenet Cornell University Roadside Ditches: A Watershed Curriculum Module

Goals: To help students understand connections between watershed land uses and stream ecosystem health To demonstrate connections between ditch runoff and streams To engage students through use of Global Positioning Systems (GPS) technology

Lake and stream health are linked to adjacent land uses and human activities.

Watershed divide Watershed: The total area above a specific point on a stream or river from which water drains toward the stream.

Photo: Y. Arthus Bertrand

Water Cycle: Balance between precipitation, evapotranspiration, infiltration, and runoff Credit:

Stream order - classifies stream segments according to the number of tributaries 2 nd Order 5 th Order

Measuring discharge: Volume of water flowing past a fixed location at any given point in time Measured in units of ft 3 /sec or m 3 /sec

Rain Baseflow (from groundwater) High flow Buttermilk Falls,NY Natural stream flow patterns Runoff Low flow

Impervious Surfaces: Rooftops Parking lots Driveways Compacted Soils: Lawns Crop fields Impacts of Land Use on Runoff

Credit:

time (hrs/days/weeks) stream height post-development pre-development Impervious surfaces impact the natural patterns of flow: frequency and magnitude of floods summer droughts (due to lower baseflow) 15% impervious surface

Impervious surfaces impact stream health: increased flooding and drought increased erosion degraded water quality loss of diversity of fish and aquatic organisms

Roadside Ditches – a neglected but critical factor in protection of water resources

After Before Ditches are managed by highway staff to prevent flooding of roads and buildings… and rarely linked to watershed management

Downstream Impacts Credit:

Watershed: 56 km 2 Stream Length: 88 km Roads: 87 km Ditches: 142 km 70% linked to stream Increased drainage density 1.6 km -1  4.1 km -1 Enfield Creek RoadStreamDivide

Total water flow Suspended sediment Dissolved chemicals Bedload sediment 8 Replicate Sampling Stations + Creek Research Doolittle, Enfield, 6-Mile Creeks

Total Bedload Sediment Collected by Ditch Type per event Grams Bare Dirt Grassy Gravel Weedy bare grassy weedy Enfield Creek – Preliminary Findings Ditch Type gravel

Downstream erosion?

Roadside Ditch Impacts: mechanism for increased land-water linkages conduit for rapid runoff internal source of sediment and other contaminants

Scraped, exposed Concrete, hardened Recommended Ditch Management Strategies Hydro-seeded Rock-lined Mowed grass

Recommendation: Disconnect ditches from streams. Use infiltration basins & detention ponds to capture water and allow it to recharge groundwater

Recommendation: Use permeable paving to reduce runoff

EPA Phase II Stormwater Regulations: Small towns/ designated MS4 communities must develop stormwater management plans by Current guidelines focus on construction activities.