Talk Outline. Roadside Ditches. Roadside Ditch Team. Roadside Drainage Networks. Methods. Study Sites 6/10/2013

Transcription

1 Roadside Ditches Improving Roadside Ditch Management Identifying and Overcoming the Hurdles Rebecca Schneider, Ph.D. Dept. Natural Resources, Cornell Local Roads Program 3 June 2013 Cornell University Summary of Research Findings Methods Findings Re plumbing Strategies Cost Estimates Barriers to Implementation Grant Options Roadside Drainage Networks Roadside Ditch Team What role do they play in: Floods? Droughts? Water pollution? Faculty: T. Walter, Dept. Biological and Environmental Engineering D. Buckley, P. Bergholz, Dept. Crops and Soils Graduate & Undergraduate Students: K. Falbo, B. Buchanan, J. Diaz Robles J. Kimchi, H. Knowlton Cornell Local Roads Program USDA # Study Sites Methods PA NY GPS and GIS mapping of ditch networks Ditch lengths Management types Connections to streams Without Ditches With Ditches Paine s Creek Watershed, Lansing, NY 1

2 Methods Ditch Study Sites Monitor Total water flow Suspended sediment Dissolved chemicals Bedload vegetated exposed, scraped Methods Hydrologic Model Results Drainage Mapping INPUTS: Slope Soils Land use Runoff Routing Methods Characteristic Watershed area Road length % road surface area of wtshd Roadside ditch length Total # of direct connections to strms Total ditch length connected to strms Area of basins draining to ditches % of watershed draining to ditches Stream channel length (no ditches) Stream channel density w/o ditches Stream channel density with ditches Average value 42.3 km 2 (16 miles km 0.69 % 81.4 km km 8.1 km % 66.0 km 1.55 (km/km2) 2.73 (km/km2) Schneider et al Results Drainage Mapping Results Hydrology Ditch drainage basins potentially intercept ~22 % of the surface runoff and shallow groundwater from each watershed and rapidly shunt it to the nearest stream. Ditch drainage basins Stream Road ditches Ditch outflows Doolittle Creek Watershed 8 ditch monitoring stations and Doolittle Crk 10 storms ; cm total rain/event Each ditch captured avg of 51% of rainfall in the ditch s basin Diaz Robles

3 Results Hydrologic Model Results Hydrology Entire Modeled Ditch Drainage Networks: Doolittle: transported 45,400 m 3 water / storm = 3.6% (+/ 1.4%) of incoming precipitation and 19.5% (+/ 9.7%) of total stream flow measured in each storm Paine s Creek: 22% of total stream flow in spring storm event and 29% of total stream flow in a summer storm event. Paine s Creek Watershed 7 ditches 34 storms mm rain April Dec Buchanan et al Results Hydrology Results Suspended Sediments spring summer TSS and Flow 10/25/05 Ditch2 Doolittle 6.00E E TSS concentration 4.00E E E E Discharge (m3/sec) Discharge (m^3/sec) 0.00E+00 0 Ditch discharges contribute to increased peak flows (avg 78%) and total flows (avg 57%) in streams. Buchanan et al Duration of storm (hrs) g ( TSS concentration Discharge Diaz Robles, 2007 Results Suspended Sediments Results Suspended Sediments Peak TSS concentration (avg kg/m3) VEGETATED TSS Concentration VS Ditch Condition % exposed bottom substrate BARE Diaz Robles 2007 TSS Doolittle Creek Watershed (62% forest 33% ag 2% developed) Avg Storm [] 0.25 g/l Max recorded [] 38.3 g/l Avg TSS load per ditch: 65 kg/storm day Total ditch network: 1,660 kg/ storm day 37% (+/ 27%) of total sediment load in Doolittle Creek (Avg of 21 days, 7 storms; range 106 6,111 kg/storm day) 3

4 Results Nutrients, Cations A diversity of chemicals dissolved in the water and adsorbed on the sediment particles are transported by ditches downstream. Nutrients Trace Metals Cations Element Total load (kg) Ortho-Phosphates 1.43 Total P NO 3- + NO Al Mn 1.48 Fe Ni 6.39 Cu 1.28 Pb 0.25 Cr 3.79 Zn 2.90 Na + 11, Mg K Ca 2+ 3, Dissolved Chemical Loads Over 10 storms De-icers Ditches are a source of sediment and associated contaminants to downstream waters, especially when scraped. Anions As Photo Bill Hecht Ditches as conduits of microbes? Ditches as conduits of microbes? Headwater farm fields 7 ditches in 4 watersheds 3forested, 4 ag fields with manure spreading 54 days July 2008 July storms 648 water samples Drinking water supplies Falbo et al Results Microbes E. coli quantification Results E. coli in ditch waters Idexx s Colilert/Quantitray Method Positive for Total Coliforms Positive for E. coli E. coli concentrations (MPN/100mL) Manure spreading Manure spreading 0 7/08 8/08 9/08 10/08 11/08 12/08 1/09 2/09 3/09 4/09 5/09 6/09 7/09 EPA STD 4

5 Results E. coli in ditch bottoms Results Bedload Bottom Sediment E. coli through Time E. coli MPN/100 ml /20/2008 7/31/2008 7/11/2008 6/21/2008 9/9/2008 Date 11/28/ /8/ /19/2008 9/29/2008 ( E. coli per 20 ml volume of surface sediment) Large quantities of gravel, rocks and other bedload move out of ditches and form deltas in the streams. Results Bedload, Discharge and Stream Geomorphology Moose River, Adirondacks High velocity discharges, bedload deltas impact stream at ~94 locations in each watershed. Summary of Research Findings Methods Findings Re plumbing Strategies Cost Estimates Barriers to Implementation Grant Options Guidelines for Improved Ditch Management BMP Bulletin For paper copies: Rebecca Schneider RLS11@cornell.edu Strategies for Re plumbing Hydroseeding: slightly increase water infiltration, reduce velocity, and capture most sediment. Check dams: slow water down, reduce incision and erosion, and capture some sediments. 5

6 Strategies for Re plumbing Strategies for Re plumbing Infiltration basins: prevents stream Flooding; increases groundwater recharge; captures all sediments Bioretention swales: reduces runoff and increases infiltration; reduces sediment and filters some nutrients. Constructed wetlands : reduces flooding; captures all sediment; removes most contaminants. Strategies for Re plumbing Win Win: Constructed Wetland Cross road underdrains: reduces flow to streams Permeable pavements: reduces most runoff; allows infiltration. Thank your Highway Department! Your tax dollars help beautify our Town and Clean Our Water Measureable Outcomes OUTCOM E Slows velocity w/in ditch Reduces stream flooding Prevents sediment frm streams Filters water denitrificatio n; microbes Summary of Research Findings Methods Findings Re plumbing Strategies Cost Estimates Barriers to Implementation Grant Options 6

7 Repair Alternative 1. Leave as is (null alternative) 2. Seed the ditch 3. Install a series of check dams 4. Fill ditch with pipe (underdrain only) 5. Fill ditch with pipe (culvert only) 6. Fill ditch with pipe (culvert and underdrain) 7. French drain (no pipe) 8. Cross road underdrain a. Straight outlets b. Distribution outlets 9. Infiltration basins a. Uphill side b. Downhill side 10. Permeable pavement layer 11. Complete fill Cost Estimates per Option Total Cost 3,591 3,644 8,495 27,835 35,461 35,948 31,366 33,567 34,167 12,000 20, ,261 24,923 Cost per Lifespan Annualized Foot (years) Cost per foot Annualized Cost per mile 1, , , , , , , , , , , , , Estimates based on 1,500 ft long ditch Candor, NY Engineering Economic Analysis by David Orr Summary of Research Findings Methods Findings Re plumbing Strategies Cost Estimates Barriers to Implementation Grant Options Barriers to Implementation 4 Main Types of Barriers Barriers to green infrastructure in the Hudson Valley: an electronic survey of implementers. Inventoried 10 Counties in Hudson River Valley Surveyed landscape architects, builders, engineers 127 responses Emily Vail and Andrew Meyer, Hudson River Estuary Program and NYSWRI, Cornell eevail@gw.dec.state.y.us; axmeyer@gw.dec.state.ny.us Other sources: Barriers and gateways to green infrastructure. Clean Water America Alliance. Barriers to Implementation Barriers to Implementation Top three barriers: (1) Costs: Need funding for design, implementation and maintenance (2) Lack of technical knowledge: not enough experience and knowledge in the development community (3) Resistance from local govt Green infrastructure is undervalued by local government; review process is hurdle; local town planning boards need education 7

8 Barriers to Implementation Summary of Research Findings Methods Findings Re plumbing Strategies Cost Estimates Barriers to Implementation Grant Options Grant Applications for Green Infrastructure Funds Generic Grant Template NYS2100 Commission Nov. 15, 2012 Gov. Andrew Cuomo convened the NYS 2100 Commission to examine and evaluate key vulnerabilities to NYS s critical infrastructure systems and to recommend actions to strengthen and improve resilience of those systems.. The commission recommends programs designed to expand green storm water infrastructure. Project Narrative Proposed Actions Measureable Outcomes Anticipated Costs Options to Consider as Match: o Hourly equipment rates allowed o Equipment operator hourly rates o Preparation labor and equipment Questions? 8