Stormwater, Climate Change, and Michigan: Part II. Alan Steinman Director, Annis Water Resources Institute Grand Valley State University

Transcription

1 Stormwater, Climate Change, and Michigan: Part II Alan Steinman Director, Annis Water Resources Institute Grand Valley State University

2 Point vs. Nonpoint Source Pollution Point sources: Nutrients come from any discernible, confined and discrete conveyance (e.g. pipe) Nonpoint sources: Nutrients come from diffuse sources (runoff from impervious surfaces, farms, yards)

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4 Nonpoint Sources of Pollution Excess fertilizers, herbicides, and insecticides from agricultural lands and residential areas Sediment from improperly managed construction sites, crop and forest lands, and eroding streambanks Livestock, pet wastes, faulty septic systems, atmosphere Oil, grease, toxics, and salt from urban runoff

5 Photo Credit: ACOGOK

6 Stormwater Facts Most of the NPS pollution comes during storm events Stormwater discharges are generated by runoff from land and impervious areas during rainfall and snow events Paved streets Parking lots Driveways and sidewalks Building rooftops

7 Stormwater Impacts 1) Increased runoff volume and velocity (i.e, flashier hydrographs) - high flows - frequency of overland flow - lag time to peak flow Credit: CEIEngineers

8 after urbanization before urbanization Time Discharge (Q) ft 3 /sec (cfs)

9 Total area = 71.2 mi 2 9

10 Upper Middle Lower Data Source: Michigan Center for Geographic Information Department of Information Technology Michigan Geographic Framework, 2003 Map Prepared January 2006 Mona Lake Watershed Council

11 % Change in Land Use: Forests Agric Open Field Lo Dens Resid. Urban/Dev

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14 HEC-HMS HMS Modeling Structure for the Mona Lake Watershed WWMS >22% impervious 9B 5B 3B 6B 15R 15C Lake Michigan R-1 ML 20C 19C 17C 18C 16R 8B 16C Legend 4B 2-10% impervious Subbasin Source 10B 7B Junction Sink Lake Channel Link Chu and Steinman (2009)

15 Water Discharges into the Mona Lake Precipitation (in) Precipitation from Sept 7, 0:00 to Sept 9, 24:00 (72 hours) Time (hr) Water Discharges into the Mona Lake Water Flow (cfs) B-FLOW 17C-FLOW 18C-FLOW 19C-FLOW 20C-FLOW /7/01 0:00 9/7/01 12:00 9/8/01 0:00 9/8/01 12:00 9/9/01 0:00 9/9/01 12:00 9/10/01 0:00 Time Chu and Steinman (2009)

16 Stormwater Impacts 2) Increased erosion & sedimentation - channel width - scour - retention of organic matter

17 Stormwater Impacts 3) Reduced recharge to aquifers Photo credit: RiverSides Photo credit: M. Ogdahl

18 Stormwater Impacts 4) Changes to Water Chemistry - increased temperature - increased levels of toxicants (oils, greases, metals) - increased levels of nutrients (N, P) Photo credit: N. DeMol

19 Photo credit: Spring Lake Lake Board

20 Harmful Algal Blooms (HABs) Microcystin is the most common cyanotoxin produced by harmful algal blooms. Hepatotoxin and tumor promoter The U.S. currently has no national standards for exposure to microcystin or other algal toxins WHO standards: 20 µg/l = recreational use 1 µg/l = drinking water Microcystin Concentrations Location Date Concentration (µg/l) Musk. Lake (open) Musk. Lake (HarborTowne) 7/16/ /16/ Mona Lake 7/23/07 317

21 Stormwater Impacts 5) Changes to Biota - declines in sensitive fish - increases in tolerant invertebrates

22 Stormwater Impacts 6) Cost of Infrastructure

23 Stormwater Impacts 1) Flashier hydrograph 2) More erosion/sediment 3) Less recharge 4) More nutrients/toxics 5) Degraded biota Urban Stream Syndrome 6) Cost of infrastructure

24 Link to Climate Change Uncertainty in climate change models increases at finer geographic scales Precipitation events in Great Lakes region >2-2.5 inches stormwater contaminants (McLellan et al. 2007) Frequency of events exceeding inch threshold will increase by 50 to 120% by end of 21 st Century (Patz et al. 2008)

25 Solutions I. Governance-related II. Best Management Practices III. Individual Behavior

26 I. Governance-related Michigan s current approach to manage water is fractured. Water is being managed, at least in part, by political instead of watershed boundaries. Water management districts (WMDs), which consolidate regulatory authority within naturally occurring watersheds, present an alternative approach to overseeing the water services of the state. This approach is perhaps most successful in the State of Florida.

27 Water defines and drives the environment of Florida Human Environment Agricultural Environment Natural Environment

28 1947 Hurricanes Two hurricanes 12 inches of rain fell in a 30 minute period In some areas, more than 100 of rainfall that year -- Courtesy of of the Sun Sentinel & Fort Lauderdale Historical Society

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31 Areas Flooded in 1947

32 Central & Southern Florida Flood Control Project Authorized by Congress 1948 Lands acquired by State Constructed by U.S. Army Corps of Engineers

33 History In 1972, the Florida Water Resources Act (Chapter 373) created six water management districts, with expanded responsibilities for regional water resource management and environmental protection. In 1976, voters approved a constitutional amendment giving the districts the authority to levy property taxes The 5 state water management districts' boundaries are determined by watersheds and other natural, hydrologic and geographic features.

34 Florida s 5 Water Management Districts

35 Water Management Districts Advantages: - Integrates permitting, water use regulation, surface and groundwater programs, surveying, land acquisition, outreach, water quality monitoring, and environmental planning in one agency - Functions at the watershed level Disadvantages: - Political entities - Priorities can shift

36 Governance-Related Recommendations Determine the feasibility and potential structure of water management districts in Michigan Evaluate feasibility of a water quality trading market in Michigan

37 Solutions II. Best Management Practices (BMPs): Structural Detention ponds Rain gardens Low Impact Development Engineer terrain, vegetation, and soil features to optimize natural infiltration, allowing the landscape to retain more of its natural hydrological function Non-Structural Ordinances

38 Solutions to Pollution Storm drain

39 Solutions III. Changing Human Behavior: Humans are crisis-oriented Education is essential, but most people respond when issue is of immediate relevance Must personalize the problem

40 Changing our behavior

41 Summary Technical approaches to stormwater must be multi-disciplinary to have best chance of success Water resource issues are not just environmental in nature; they also include political, social, and economic elements effective solutions must address all these elements

42 Acknowledgements Colleagues Elaine Sterrett Isely, AWRI-GVSU Mary Ogdahl, AWRI-GVSU Kurt Thompson, AWRI-GVSU Paul Isely, Seidman-GVSU Tim Penning, Communications-GVSU ECT Inc., Ann Arbor Chuck Pistis, MI Sea Grant Dan O Keefe, MI Sea Grant Funding US Department of Transportation MI Sea Grant