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Rusty Russell MAS 2019

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Presentation for the 2019 Massachusetts Sustainable Communities and Campuses Conference on March 29, 2019 in Cambridge, MA

Publicada em: Meio ambiente
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Rusty Russell MAS 2019

  1. 1. NATURE-BASED 
 WATERSHED SOLUTIONS:
 TAKING THE 
 TECHNIQUES 
 BEYOND TALK Rusty Russell, Executive Director Merrimack River 
 Watershed Council Massachusetts Sustainable 
 Communities and Campuses Cambridge, Mass. Friday, March 29, 2019 2-2:55 p.m.
  2. 2. What Is a “Watershed?” Defining our terms: “Watershed”
  3. 3. Merrimack Watershed consists of: Merrimack “main stem”
 and Sub-watersheds: • Beaver • Cohas • Concord • Contoocook • Nashua • Pemigewasset • Piscataquag • Powwow • Salmon • Shawsheen • Soucook • Souhegan • Spicket • Stony Brook • Suncook • Winnipesaukee
  4. 4. Clean Water Act of 1972 – 
 Results Are Hard to Miss! 1960s 2010s Nashua River, a major tributary
  5. 5. IN MASSACHUSETTS, 
 IMPERVIOUS COVER IS INCREASING Source: Mass Audubon, Losing Ground—Planning for Resilience (June 2014), p. 3
  6. 6. AND SO IS (EXTREME) PRECIPITATION Climate Science Special Report: Fourth National Climate Assessment, Volume 1, U.S. Global Change Research Program (2017), p. 212 Four measures of increasing rainfall over past 115 and 58 years (in each, the greatest spike is in Northeast, with rate increasing over time) 92% increase 74% increase 55% increase 27% increase
  7. 7. THE RESULT: 
 MORE STORMWATER POLLUTION How does it happen? ▪ Impervious cover prevents water from infiltrating (or percolating) into the soil ▪ This changes the water cycle from 10% surface runoff and 50% infiltration to just 15% infiltration and 55% surface runoff ▪ Runoff picks up all kinds of contaminants ▪ Polluted stormwater runs untreated into the river Increased surface runoff from the built environment is called STORMWATER POLLUTION
  8. 8. WHAT’S WRONG WITH MORE RUNOFF? ▪ It’s polluted – by trash, chemicals,
 bacteria, sediments ▪ It can lead to more flooding ▪ It can intensify droughts ▪ It triggers combined sewer overflows ▪ It’s a lost resource….
  9. 9. NEW EPA STORMWATER PERMIT PROGRAM: 
 EFFECTIVE JULY 1, 2017 
 
 MS4: “MUNICIPAL SEPARATE STORM SEWER SYSTEM” ▪ MS4 is part of the federal Clean Water Act ▪ Nearly all of eastern Massachusetts is a “small MS4” area 
 and must develop a stormwater management plan 
 to reduce polluted stormwater runoff by: • Educating residents, businesses, and developers • Testing for leaking sewage from stormwater pipes • Controlling construction-site discharge • Retaining or treating runoff from development • Ensuring that streets and catch basins are clean
  10. 10. MS4 – Phase 2 communities: ▪ MA = 260 ▪ CT = 221 ▪ NH = 37 ▪ RI = 34 US Total = 6695 MS4 Ph. 2 Coverage: ▪ 4% US land area ▪ > 80% of US population
  11. 11. HOW CAN WE DEAL WITH RUNOFF? Reduce pollutants— Keep streets clean, scoop up, use fewer yard chemicals Capture/treat runoff— Take advantage of “gray infrastructure” like detention ponds and filters Protect land— Maintain natural areas, 
 especially in urban settings
  12. 12. OR, USE “GREEN INFRASTRUCTURE” (GI)
 
 ▪ Water infiltrates soil and groundwater ▪ Water flow slows down, reducing flooding and erosion ▪ Plants and soil
 filter pollutants ▪ Sediments and trash are captured, then removed ▪ Native plants
 create habitat e.g., a bioretention cell
  13. 13. IDEA: BUILD A RAIN GARDEN –
 IN YOUR OWN BACKYARD
  14. 14. HOW (AND WHERE) DO I BUILD ONE? Choosing the Site ▪ Natural runoff spot ▪ Residential – generally 100-300 ft2 (10-20 feet in diameter) ▪ Often filtering runoff from roof or driveway ▪ Usually 5-7% of area that drains to the rain garden ▪ Slope < 20% ▪ 6-9 inches ponding depth treats 0.5-1 inch of runoff ▪ Groundwater layer is at least 6 feet deep Choosing the Materials ▪ Four layers: • Gravel at bottom • Then pea stone • Then bioretention soil ✓ 40-65% sand ✓ 20-30% topsoil ✓ 15-40% compost • Mulch at top ▪ Total depth: 24-48 inches ▪ Should drain in less than 72 hours
  15. 15. ▪ Native species ▪ Herbaceous perennials and shrubs ▪ Plants that tolerate: • Frequent ponding • Saline conditions • Extended dry periods ▪ Species should vary based on proximity to center (lowest point) ▪ Many on-line lists; try: University of New Hampshire Cooperative Extension and New Hampshire Department of Environmental Services, Native Plants for New England Rain Gardens, 2016, at: https://extension.unh.edu/resources/ files/Resource005899_Rep8265.pdf WHAT CAN YOU GROW THERE?
  16. 16. HOW MUCH WILL IT COST? 
 HOW MUCH MAINTENANCE IS NEEDED? Cost… ▪ Self-install: $2-$5 per ft2 ▪ Contractor installation: $8-$12 per ft2 ▪ For 150 ft2 rain garden: • $300-$750 if DIY • $1200-$1800 if contracted Maintenance… ▪ Prune back dead leaves and branches in spring ▪ Replant as needed ▪ Weed, especially during first few months ▪ Mulch every 2-3 years to maintain 3-inch depth ▪ Remove excess sediment once or twice a year
  17. 17. HOW DOES IT WORK? WHAT DOES IT DO? The How… ▪ Sedimentation ▪ Filtration ▪ Adsorption (adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface, creating a film) ▪ Absorption (fluid is dissolved by or permeates a liquid or solid, respectively) ▪ Cation Exchange Capacity ▪ Polar / Non-polar Sorption ▪ Microbial Action (aerobic / anaerobic) (decomposition / nitrification /denitrification) ▪ Plant Uptake ▪ Cycling Nutrients / Carbon / Metals ▪ Biomass Retention (Microbes / Plant) ▪ Evaporation / Volatilization The What… (pollutant reductions) ▪ Total suspended solids (TSS) – with filter strip – 90% ▪ Nutrients • Total N – 30-50% • Total P – 30-90% ▪ Metals – 40-90% • Lead • Zinc • Cadmium • Copper ▪ Ammonia – 90% ▪ Bacteria – uncertain, but possible (90% in box experiment) ▪ Oil and Grease – 95% in box experiment
  18. 18. And this can be done on a larger scale – GIS analysis of Aberjona River watershed (Burlington, Winchester, Woburn and Reading)
  19. 19. High feasibility: 
 Group A (sand, loamy sand or sandy loam soils, with low runoff potential and high infiltration rates) Group B (silt loam or loam) High feasibility: sand/gravel/ alluvium
  20. 20. High feasibility:
 <25% slope High feasibility:
 2-7 feet
  21. 21. APPLYING THE CONCEPT IN DENVER
  22. 22. Combined Sewer Overflows (2018) CCSO Totals (2018)
  23. 23. POLLUTED STORMWATER CONTROL— CHALLENGES AHEAD ▪ Multiple impacts, complex and incremental: • Physical structure of streams • Ecological health and aquatic habitat • Water quality and quantity • Local economy ▪ Impacts less visible/perceptible ▪ Impacts skew towards ecosystem health ▪ Difficult group action problem ▪ Large number of sources/avenues ▪ May be seen by some as effort to limit 
 development and private property “rights” ▪ Local equity issues may be significant ▪ May be re-cast as “unfunded mandate” ▪ Political climate unfavorable
  24. 24. THE NEXT SET OF CHALLENGES:
 ▪ What % of polluted stormwater can GI/LID remove? ▪ How will total costs compare with “engineered” solutions? ▪ Can the public and its officials successfully transition to a more low- tech approach that: • Requires more frequent (but simple) maintenance? • Calls for new knowledge? • Is localized and highly diffuse? • May call for more cooperation than has been customary? ▪ How can GI/LID be woven into a strict system of private property? ▪ How can co-benefits be incorporated into the calculation? ▪ What economic drivers will make this happen? 
 (think “stormwater utility”)
  25. 25. Thank You! Questions? rrussell@merrimack.org ?

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