roadside ditches, stormwater management, and stream … · roadside ditches, stormwater management,...

Roadside Ditches, Stormwater Management,

and Stream Health in New York

Rebecca SchneiderRoadside Ditch ProgramDept. Natural Resources,

Cornell University Juan Diaz-Robles (CEE), Art Lembo (CSS)Nancy Trautmann, (DNR), Todd Walter (BEE)Sharon Anderson (Cayuga Lake Watershed Network)

Quantity and quality of water in our lakes and streams,

arelinked to

adjacent landuses and human

activities.

ImperviousSurfaces:RooftopsParking lotsDriveways

Compacted Soils:Lawns,Crop fields

E.P.A. Phase II Stormwater Regulations 2003For 450 towns in New York – Municipal Separate Storm Sewer Systems

Rt. 89, Tompkins Co., Feb 2006

Main focus is on construction activities

Roadside Ditches:the unrecognized factor

in stormwaterrunoff management

Managed by highway staffTo prevent traffic accidents

Rarely linked to watershed Management issues

Roadside Ditch Program

RESEARCH Objectives:

• How do different ditch management practices affect the quantity and type of materials movinginto streams (TSS, bedload, dissolved chemicals, water)?

2) What percentage of the total stream load and flow is contributed by the network of ditches in a watershed?

3) Can we develop a model that estimates ditch loadingsbased on internal or external land use characteristics?

EXTENSION Objectives:

1) Build awareness of the issue and alternative managementpractices for town highway staff and town planners.

2) Educate youth about ditches and how they affect streams.

ENFIELD6-MILE

DOOLITTLE

Susquehanna R.

Cayuga Lake

exposed

vegetated

stream

Station type:

Research Study Sites

8 SamplingStations +

Creek

Site 4

Site 2

Site 6

Site 1

• Total water flow• Suspended sediment• Dissolved chemicals

• Bedload sediment

8 ReplicateSampling Stations

+ Creek

ResearchDoolittle, Enfield,

6-Mile Creeks

Ditches: 142 km70% linked to stream,largely in 1st order,headwaters.

Stream Channel Density1.6 km-1 to 4.1 km-1

Enfield Creek

Road length 87 km

Stream length 88 km

Divide 56 km 2 in size

Vegetated

Scraped, exposed

Preliminary Findings

00.40.81.21.6

22.42.83.23.6

44.44.8

Pea

k co

ncen

tratio

nof

TS

S (g

/L)

0 8.3 13.7 41.7 64.3 71.7 90.2 97.5 100

Percent of Scrapedor exposed substrate

12345 (f5 (t678

Ditch #

Suspended sediment loadsare significantly higher from

scraped ditches.

Significant quantitiesof bedload transportmove in scraped andexposed ditches.

Roadside Ditch Impacts

1) Mechanism for increasedland-water linkages

2) Intercept and divert runoffrapidly to stream.

3) Internal source of sediment and other contaminants

Recommendation:Don’t scrape ditches and leavethem exposed to erosion duringstorm events.

Extension To Town Highway Dept. and

Town Planners

17 presentations to 1000 stakeholders

Recommendation:Use infiltration Basins / Detention Ponds to capture water and allow it to recharge groundwater

K-12 Curriculum on Roadside Ditches: students learn to use GPS and map their ditches on the Website

http:// ei.cornell.edu/watersheds/ditches