COUNTYWIDE IMPLEMENTATION STRATEGY TMDL AND IMPERVIOUS SURFACE RESTORATION PLAN HOWARD COUNTY, MARYLAND DECEMBER 2015 COUNTYWIDE IMPLEMENTATION STRATEGY DECEMBER 2015 PREPARED FOR HOWARD COUNTY, MARYLAND STORMWATER MANAGEMENT DIVISION DEPARTMENT OF PUBLIC WORKS 6751 COLUMBIA GATEWAY DRIVE, SUITE 514 COLUMBIA, MD 21046-3143 PREPARED BY KCI TECHNOLOGIES, INC. 936 RIDGEBROOK ROAD SPARKS, MD 21152 WITH SUPPORT FROM MCCORMICK TAYLOR, INC. TH 509 S. EXETER STREET, 4 FLOOR BALTIMORE, MD 21202 Countywide Implementation Strategy 2015 Acknowledgements This watershed restoration plan was completed as a collaborative effort between the following partners: Howard County Stormwater Management Division KCI Technologies, Inc. McCormick Taylor, Inc. The report was authored by the following individuals from KCI Technologies, Inc.: Megan Crunkleton Mike Pieper Bill Frost, P.E. Database support and GIS analyses were provided by McCormick Taylor, Inc.: Joe Knieriem County staff providing expertise, oversight, and review include: Kelly Hargadin Christine Lowe, P.E. Mark Richmond, P.E. Appropriate citation for the CIS is as follow: KCI Technologies, Inc. 2015. Countywide Implementation Strategy. Prepared by KCI Technologies, Inc., Sparks MD for Howard County Department of Public Works, Stormwater Management Division, Columbia Maryland. Dated December 2015. For more information pertaining to the CIS, please contact: Mark S. Richmond, Chief Stormwater Management Division Howard County Department of Public Works 6751 Columbia Gateway Drive, Suite 514 Columbia, MD 21046 410-313-6413 [email protected] And visit us on the web: http://www.howardcountymd.gov/swm.htm ii Howard County DPW Countywide Implementation Strategy 2015 Table of Contents Executive Summary .......................................................................................................... ES-1 1 Introduction ................................................................................................................... 1 1.1 Background and Purpose .............................................................................................................. 1 1.1.1 Howard County MS4 Permit ................................................................................................. 1 1.1.2 MS4 Permit Coverage ........................................................................................................... 4 1.2 TMDL Allocations and Impervious Restoration Targets................................................................ 5 1.2.1 Local TMDLs .......................................................................................................................... 5 1.2.2 Chesapeake Bay TMDL ........................................................................................................ 11 1.2.3 Impervious Restoration ....................................................................................................... 12 1.3 Restoration Plan Elements and Structure ................................................................................... 15 2 Causes and Sources of Impairment ............................................................................... 18 2.1 Impairments ................................................................................................................................ 18 2.1.1 Water Quality ...................................................................................................................... 18 2.1.2 Biological Impairments ....................................................................................................... 19 2.2 Sources ........................................................................................................................................ 21 2.2.1 Land Use/Land Cover .......................................................................................................... 23 2.2.2 Impervious Surfaces ............................................................................................................ 27 2.3 Anticipated Growth ..................................................................................................................... 30 2.3.1 Offsetting Loads from Future Growth ................................................................................ 30 2.3.2 Estimates of Future Growth ................................................................................................ 30 3 Management Measures ............................................................................................... 34 3.1 County Planning Process ............................................................................................................. 34 3.1.1 Watershed Assessment - 2015............................................................................................ 34 3.1.2 Watershed Assessment – 2016 ........................................................................................... 37 3.1.3 Project Implementation ...................................................................................................... 37 3.2 Modeling Approach..................................................................................................................... 38 3.3 Best Management Practices ....................................................................................................... 39 4 Expected Load Reductions and Impervious Treatment .................................................. 48 4.1 2015 Progress – Actual Implementation .................................................................................... 48 4.1.1 Local TMDLs ........................................................................................................................ 48 4.1.2 Chesapeake Bay TMDL ........................................................................................................ 51 4.1.3 Impervious Restoration ....................................................................................................... 51 4.2 Planned Implementation ............................................................................................................ 53 4.2.1 Local TMDLs ........................................................................................................................ 57 4.2.2 Chesapeake Bay TMDL ........................................................................................................ 59 4.2.3 Impervious Restoration by 2019 ......................................................................................... 60 5 Technical and Financial Assistance Needs ..................................................................... 62 5.1 Technical Requirements .............................................................................................................. 62 iii Howard County DPW Countywide Implementation Strategy 2015 5.2 Financial Needs ........................................................................................................................... 63 5.2.1 Project Cost Estimates – Watershed Assessment ............................................................... 63 5.2.2 CIS Cost Estimate ................................................................................................................ 63 5.2.3 Cost Summary ..................................................................................................................... 65 6 Public Participation / Education ................................................................................... 68 6.1 CIS and Watershed Assessment Public Participation ................................................................. 68 6.2 Program Summary ...................................................................................................................... 68 6.2.1 Stormwater Management Division (SWMD) Education Programs ..................................... 69 6.2.2 Recycling Division Programs ............................................................................................... 69 6.2.3 Department of Recreation and Parks (DRP) Programs ....................................................... 70 7 Implementation Schedule and Milestones .................................................................... 71 8 Load Reduction Evaluation Criteria ............................................................................... 74 8.1 Tracking Implementation of Management Measures ................................................................ 74 8.2 Estimating Load Reductions ........................................................................................................ 76 8.3 Tracking Overall Program Success through Monitoring ............................................................. 76 8.4 Best Management Practices Inspection and Maintenance ........................................................ 76 9 Monitoring................................................................................................................... 77 9.1 Current Howard County Monitoring ........................................................................................... 78 9.2 Recommended Monitoring to Track Implementation Progress ................................................. 81 10 References ................................................................................................................... 85 List of Tables ES Table 1. Howard County Local TMDL Summary .................................................................................. ES-3 ES Table 2. CIS Planned