7 14-2010 cp resource assessment

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A look at the trends for water resources in teh Coon Creek watershed in Anoka County, MN. This is part of our 10-year planning process.

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7 14-2010 cp resource assessment

  1. 1. Coon Creek Watershed District Water Resource Assessment & Issues July 14, 2010
  2. 2. Agenda (7/14/10) <ul><li>1. Introductions </li></ul><ul><li>2. Review from 3/30/10 Meeting </li></ul><ul><li>3. Review of Stated Issues & Concerns </li></ul><ul><li>4. Changes in Resource Conditions </li></ul><ul><li>5. Demands for Resource Uses </li></ul><ul><li>6. Water Management Issues </li></ul>
  3. 3. 3/30 Meeting Review Approach & Process * Agency Review * Implementation: Goals & Measures * Issues & Concerns * - Resource Trends & Implications * Review Requirements & Issues Q1 Q4 Q3 Q2 Q1 2011 2010
  4. 4. Local Agency Attendance * * CLAA * * * * * 3/30 * Coon Rapids * Ham Lake Columbus * Blaine * Andover * Anoka County * ACD 7/14 Invites
  5. 5. State Agency Attendance * * * * 7/14 DA-agriculture DH -health - DOT * PCA * Met Council * DNR * BWSR 3/30 Invites
  6. 6. March Meetings 3. Review of Stated Issues & Concerns
  7. 7. CCWD Board Issues & Concerns 3/8/10 Working through with State Agencies Water quantity vs. quality conflicts Many physical resource needs may be beyond our control Groundwater-Surface Water Connection Getting ahead of increasing water quality concerns Effective and quick enforcement Enforcement Concern Issue
  8. 8. Planning Advisory Group Issues & Concerns 3/30/10 6. Credit for ponds that infiltrate 5. Infiltration - groundwater effect 4. Buffer Strips 3. Earth Friendly Ditch Management – Multiple Use 2. Lake Management Plans for other lakes 1. Water Quality- TMDLs: City Involvement 12. Groundwater Modeling standards 11. Effect of Mining/dewatering on wetlands – subwatershed 10. Document District Retrofit efforts 9. Document collaboration with I&E efforts 8. Wetland Functions & Values assessment 7. Coordination of monitoring for state/other permit reports
  9. 9. BWSR Initial Issues & Concerns Include budget; key water bodies, party collecting data; type of data collected; Trends Detailed Water Monitoring Program For use in grant applications O&M & Capital Prioritization General Schedule Reasonable & Measurable Goals & Objectives City environmental committees, Neighborhood Assoc. Public Involvement Process Status of Progress – What has been completed? Notes Issue/Concern
  10. 10. MPCA Initial Issues & Concerns 4. Implementation schedule & responsibilities 3. Stormwater runoff goals and standards 5. Wetland Functions & Values 7. Monitoring Program 2. Impaired waters goals 6. Wetland Regs. consistent w/ MR 7050 1. LID/MID Principles
  11. 11. Summary <ul><li>18 issues raised: </li></ul><ul><ul><li>7 Physical Resources </li></ul></ul><ul><ul><li>11 Managerial/Compliance </li></ul></ul>
  12. 12. Physical Resource Issues Comprehensive Plans Lakes Functional Assessment Wetlands General Water Quality Quality vs Quantity tradeoffs Water Quality Effect of infiltration on GW Quality Effects of dewatering Groundwater x Surface water Groundwater
  13. 13. Managerial Issues Naturalized Ditch Design Policy & Planning Benefits & Priorities Values Credits Principles (LID/MID &7050) Coordination Enforcement & Regulation Standard approach Modeling Comp Plan, TMDL Involvement/Coordination Schedule Goals & Objectives Measures Performance & Document
  14. 14. Online: www.cooncreekwd.org Reviews Current Plan 2000-2009 Changes & Trends Implications of Changes & Trends 2020 Management Expectations 4. Changes in Resource Conditions
  15. 15. Precipitation <ul><li>Less annual precipitation </li></ul><ul><li>Greater occurrence of larger events over smaller areas </li></ul>CCWD 2010
  16. 16. Precipitation Frequency of occurrence remains the same CCWD 2010
  17. 17. Evapotranspiration <ul><li>Less Excess Precipitation </li></ul><ul><li>= Less Natural Recharge </li></ul>CCWD 2010
  18. 18. Surficial Groundwater Landscapes River Terrace Lake Deposits
  19. 19. Generalized Profile (Upper 120 ft) MPCA 1997 River Terrace Lake Deposits Water Table Sand Clay Direction of Flow
  20. 20. Surficial Groundwater Used Elevation change 1978 to 2008 CCWD 2010
  21. 21. Surficial Groundwater <ul><li>Effective ground watershed is slightly larger than surface watershed </li></ul><ul><li>Less groundwater available </li></ul><ul><li>More difficult to maintain surface water resources driven by groundwater </li></ul><ul><li>More differentiation across the watershed </li></ul>
  22. 22. Surface Water <ul><li>Ponding/ Rate control is working </li></ul><ul><li>Flashy lower portion of the watershed remains (Coon Rapids) </li></ul>Montgomery-Watson 1999 Wenck & Assoc 2009
  23. 23. Lakes <ul><li>Declines in water levels in Lakes and wetlands </li></ul><ul><li>Water quality has significantly improved from 1983 to 2009 </li></ul><ul><ul><li>Secchi transparency has an improving trend since 1993 </li></ul></ul><ul><ul><li>Total phosphorus and chlorophyll-a are statistically unchanged </li></ul></ul>ACD 2009 Met Council 2009
  24. 24. Water Quality <ul><li>Impaired for Biota TMDL=(TSS + DO) </li></ul><ul><li>Exceeding standards for </li></ul><ul><ul><li>Turbidity </li></ul></ul><ul><ul><li>Total Suspended Solids </li></ul></ul><ul><ul><li>Phosphorus </li></ul></ul><ul><li>Lower (older) portion of the watershed lacks infrastructure needed for water quality </li></ul>ACD 2009
  25. 25. Wetlands <ul><li>Probable loss of 52% of wetland stock </li></ul>Met Council 2009
  26. 26. Wildlife <ul><li>Need to model Habitat needs for critical natural elements (E,T, & SC species & communities) </li></ul><ul><li>Fishery potentially stressed with lower lake levels </li></ul>Native Vegetation
  27. 27. 5a. Direct Demands <ul><li>People </li></ul><ul><li>Land </li></ul><ul><ul><li>Transportation </li></ul></ul><ul><ul><li>Mining </li></ul></ul><ul><li>Drainage </li></ul><ul><ul><li>Agriculture </li></ul></ul><ul><ul><li>Dewatering </li></ul></ul><ul><li>Water </li></ul><ul><ul><li>Irrigation </li></ul></ul><ul><ul><li>Aesthetics </li></ul></ul>
  28. 28. Population Trends 1.3% average annual growth 13% 139,307 16,686 44,005 623 50,987 27,006 2020 12% 123,649 Total 13% 22% Change 11% 15,017 Ham Lake -1% 44,479 Coon Rapids 23% 508 Columbus 29% 39,597 Blaine 12% 24,048 Andover Change 2010
  29. 29. Land <ul><li>7,500 acre decrease in agricultural land </li></ul><ul><li>Estimated 7,800 acre increase in impervious surface - mostly in headwaters </li></ul>
  30. 30. Drainage <ul><li>Demand decreases </li></ul>
  31. 31. Water – Surficial Aquifer <ul><li>Estimated 2.8 BGY average over last 22 years </li></ul>Ditches and groundwater could become an increasing source of water for commercial uses
  32. 32. Transportation <ul><li>More aggressive winter maintenance (salt & sand = Chlorides & TSS) </li></ul><ul><li>More impervious area </li></ul>
  33. 33. Mining/Dewatering <ul><li>Decrease in Groundwater Supplies </li></ul><ul><li>Changes in Wetlands, Trees and Parks </li></ul><ul><li>Land Subsidence </li></ul>
  34. 34. Recreation <ul><li>Increased interest in navigation of the Creek </li></ul><ul><li>Increased evaluation of ditch corridors for trail purposes </li></ul>
  35. 35. Public Land <ul><li>19.7% of land tax exempt </li></ul><ul><li>Contribution to loadings and associated costs becomes an issue </li></ul><ul><li>Increased need for SWPPPs/SAMPs </li></ul>
  36. 36. Flood Control Groundwater Recharge Water Quality 5b. Indirect Demands
  37. 37. Flood Control <ul><li>More “localized” Regional flood events </li></ul><ul><li>Storms outside the “normal” distribution </li></ul><ul><ul><ul><li>Higher Highs </li></ul></ul></ul><ul><ul><ul><li>Lower Lows </li></ul></ul></ul>
  38. 38. Groundwater Recharge <ul><li>Only way to influence surficial groundwater </li></ul><ul><li>Need 15 to 20,000 AFPY for 10 Years to return to 1988 elevations (CCWD) </li></ul>
  39. 39. Water Quality & Stormwater TMDL Develop Biota Maintain Volume Maintain Dissolved Oxygen 2.5 Reduce Phosphorus 8 Reduce TSS 3 Reduce Turbidity Factor Action Parameter
  40. 40. 7. Water Management Issues
  41. 41. Temporal Issues Thinking about the next 10 years Precipitation 30” per yr + 2” Continue to Decline < 28” per yr (40%) Return to Normal 30” + 2 (40%) Increase >33” per yr (20%) Get Drier Stays Dry Gets Wet
  42. 43. Key Issues Evaluate 100 yr event Extreme Storm Control post development peak to predevelopment rate Overbank Flood Protection Reduce erosive velocities & unstable conditions Channel Protection Infiltrate to predevelopment Soil Hydro group Groundwater Recharge Retain some of the load by capturing amount or volume Water Quality Volume Need Issue
  43. 45. Management Issues <ul><li>Which rainfall event or runoff volume should be the basis for computing water quality volume: </li></ul>3.0 ac-ft 1.25” Pitt Method 6.2 ac-ft 2.3” 1 Yr-24 hr Storm 3.4 ac-ft 1.5” 95% Annual Rainfall 2.6 ac-ft 1.15” 90% Annual Rainfall WQ Volume Rainfall Amt Option
  44. 46. Obvious Issues & Concerns From Resource Assessment
  45. 47. Obvious Issues Supply & Capacity <ul><li>Precipitation </li></ul><ul><ul><li>Less annual precipitation </li></ul></ul><ul><ul><li>Greater occurrence of larger precipitation events over smaller areas </li></ul></ul><ul><ul><li>Less Excess Precipitation = Less Natural Recharge </li></ul></ul>
  46. 48. Obvious Issues Supply & Capacity <ul><li>Groundwater </li></ul><ul><ul><li>Less groundwater available </li></ul></ul><ul><ul><li>More difficult to maintain surface water resources </li></ul></ul><ul><li>Lakes & Wetlands </li></ul><ul><ul><li>Declines in water levels in Lakes and wetlands </li></ul></ul><ul><ul><li>Probable loss of 52% of wetlands </li></ul></ul>
  47. 49. Obvious Issues Supply & Capacity <ul><li>Surface Water </li></ul><ul><ul><li>Flashy lower portion of the watershed </li></ul></ul><ul><ul><li>Short bursts of high volume/high velocity runoff events on sandy substrates and impervious surfaces </li></ul></ul>
  48. 50. Obvious Issues Direct-Demand & Utilization <ul><li>Land </li></ul><ul><ul><li>7,800 acre increase in impervious surface mostly in headwaters </li></ul></ul><ul><li>Drainage </li></ul><ul><ul><li>7,500 acre decrease in agricultural land </li></ul></ul><ul><li>Water Source </li></ul><ul><ul><li>Ditches and groundwater become an increasing source of water for commercial uses </li></ul></ul>
  49. 51. Obvious Issues Indirect Demand <ul><li>Flood Control </li></ul><ul><ul><li>More “localized” Regional flood events (Andover x Ham Lake) </li></ul></ul><ul><li>Groundwater Recharge </li></ul><ul><ul><li>Need approximately 15 to 20,000 AFPY for 10 Years to return to 1988 elevations </li></ul></ul><ul><li>Water Quality </li></ul><ul><ul><li>Biota </li></ul></ul><ul><ul><li>Turbidity, TSS, Phosphorus </li></ul></ul>
  50. 52. Issue Chain Decline in Precipitation Decrease in Groundwater Recharge Decline in Surficial Groundwater Levels Decline in Lake levels, Wetlands Increased Need to Irrigate Decreased Need To Drain Further Decline in Groundwater Levels Increased Stress on Fishery & Wildlife Decrease in Recreational Use Increase in “dry” Marginal Land Higher Intensity Rainfall Events Increased Volume & Rate of Runoff Increased Potential For Local Flooding Increased Erosion TSS & Turbidity Increased Stress on Fishery & Biota More Involved Site Assessments Increased Water Harvesting Increased Potential For Local Flooding Increase in Dewatering Increased Evaporative Loss thru Lakes

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