DRAFT Wicomico River
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Final Wicomico River Watershed Management Plan - Updated April 2014 PREPARED FOR: PREPARED BY: 8390 Main Street, 2nd Floor Ellicott City, MD 21043 www.cwp.org This page has intentionally been left blank. Wicomico River Watershed Management Plan Table of Contents EXECUTIVE SUMMARY........................................................................................ viii SECTION 1. INTRODUCTION ................................................................................... 1 1.1 Process for Developing the Wicomico Watershed Management Plan ..................... 1 1.2 U.S. EPA Watershed Planning “A-I Criteria” ......................................................... 2 1.3 Plan Organization .................................................................................................. 3 1.4 Caveats .................................................................................................................. 4 SECTION 2. WATERSHED CHARACTERIZATION .............................................. 5 2.1 Introduction ........................................................................................................... 5 2.2 Stream Conditions ................................................................................................. 9 2.2.1 Total Maximum Daily Loads......................................................................... 10 2.2.2 Biological Conditions .................................................................................... 12 2.2.3 Water Quality Conditions .............................................................................. 16 2.2.4 Sources of Impairment .................................................................................. 21 2.3 Natural Resources ................................................................................................ 23 2.3.1 Ecological Areas ........................................................................................... 23 2.3.2 Protected Lands ............................................................................................. 27 2.4 Classification of Subwatersheds ........................................................................... 28 2.5 Sea Level Rise ..................................................................................................... 30 SECTION 3. WATERSHED ASSESSMENT PROTOCOLS ................................... 32 3.1 Introduction to the Watershed Assessment ........................................................... 32 3.2 Stormwater Retrofit Inventory ............................................................................. 32 3.3 Unified Subwatershed and Site Reconnaissance ................................................... 34 3.3.1 Hotspot Investigations ................................................................................... 34 3.3.2 Neighborhood Source Assessment................................................................. 35 3.4 Unified Stream Assessment ................................................................................. 36 3.5 Identification of Protection Opportunities ............................................................ 36 SECTION 4. FINDINGS ............................................................................................. 39 4.1 Subwatershed Assessment General Findings ........................................................ 39 4.1.1 Nomenclature ................................................................................................ 39 4.1.2 General Findings ........................................................................................... 40 4.1.3 Lakes and Ponds ........................................................................................... 44 4.1.4 Tree Planting Opportunities........................................................................... 46 4.2 South Prong Subwatershed Findings .................................................................... 47 4.2.1 South Prong Overview .................................................................................. 47 4.2.2 South Prong Field Assessment and Findings ................................................. 49 4.2.3. South Prong Protection Strategy ................................................................... 59 i Wicomico River Watershed Management Plan 4.3 Tony Tank Subwatershed Findings ...................................................................... 61 4.3.1 Tony Tank Overview .................................................................................... 61 4.3.2 Tony Tank Field Assessments and Findings .................................................. 63 4.3.3. Tony Tank Protection Strategy ..................................................................... 74 4.4 North Prong Subwatershed Findings .................................................................... 76 4.4.1 North Prong Overview .................................................................................. 76 4.4.2. North Prong Field Assessments and Findings ............................................... 78 4.4.3. North Prong Protection Strategy ................................................................... 92 SECTION 5. ACTION PLAN ..................................................................................... 94 5.1. Watershed Restoration Action Strategies............................................................. 94 5.2 Implementation Planning and Costs ..................................................................... 98 5.3 Monitoring Plan ................................................................................................. 109 5.4 Project Tracking ................................................................................................ 110 5.5 Long Term Goals ............................................................................................... 110 REFERENCES .......................................................................................................... 111 List of Figures Figure 2. 1. Wicomico River Watershed .................................................................................8 Figure 2. 2. Location and Ranking of Fish Index of Biological Integrity (FIBI) Sites ............ 14 Figure 2. 3. Location and Ranking of Benthic Macroinvertebrate Index of Biological Integrity (IBI) Sites ............................................................................................................................. 15 Figure 2. 4. Average Monthly Total Nitrogen Concentration (mg/l) ...................................... 17 Figure 2. 5. Average Monthly Total Phosphorus Concentration (mg/l) .................................. 17 Figure 2. 6. Total Phosphorus Values for Selected Creekwatcher Sampling Sites .................. 19 Figure 2. 7. Total Nitrogen Values for Selected Creekwatcher Sampling Sites ...................... 20 Figure 2. 8. E.coli and Total Coliform Concentrations in Salisbury Outfalls ......................... 22 Figure 2. 9. Protection and restoration subwatershed priorities as identified by the Core Team ............................................................................................................................................. 30 Figure 2. 10. Sea level rise inundation scenarios for the Wicomico River watershed ............. 31 Figure 4. 1. Wet pond with weir outlet structure to road ditch ............................................... 41 Figure 4. 2. Rain garden opportunity at Prince Street School ................................................ 42 Figure 4. 3. Opportunity for ditch restoration in SP_NSA_6. ................................................ 43 ii Wicomico River Watershed Management Plan Figure 4. 4. Better site design and stormwater treatment reduce phosphorus loading (Caraco, 2001) .................................................................................................................................... 45 Figure 4. 5. Soil distribution across the South Prong subwatershed ....................................... 48 Figure 4. 6. (a) Bioretention opportunity at SP_RRI_15A; (b) sediment build-up in Ward Museum parking lot (SP_RRI_305A); and (c) existing wet pond at SP_RRI_17 could be retrofit to provide additional water quality treatment............................................................. 50 Figure 4. 7. (a) Opportunity for stormwater treatment at SP_NSA_15; (b) Opportunity for tree planting around a stormwater pond at SP_NSA_5; and (c) Opportunity for ditch restoration at SP_NSA_6 ........................................................................................................................... 54 Figure 4. 8. (a) Commercial vehicle washing on impervious cover (HSI_20a) and (b) improperly stored materials (HSI_20b) ................................................................................. 54 Figure 4. 9. (a) RCH 13 - "excellent reach" and (b) channelized section of RCH4 - "poor" reach..................................................................................................................................... 57 Figure 4. 10. (a) Impacted buffer (IBI 701) has been overrun with invasive Japanese knotweed and (b) channel modification (CM 3101) at the airport.......................................................... 58 Figure 4. 11. (a) Very poor stream reach with no buffer and hardened banks (SP_RCH_8); (b) Excellent stream reach with floodplain access and good buffer (SP_RCH_33); and (c) Opportunity for buffer enhancement (SP_IB_501) ...............................................................