WATERSHED PROTECTION AND RESTORATION PLAN FOR THE MANALAPAN BROOK WATERSHED Middlesex and Monmouth Counties, New Jersey Prepared for: New Jersey Water Supply Authority, on behalf of the Manalapan Brook Watershed Restoration and Protection Plan Project Committee Watershed Protection Programs 74 East Main Street Somerville, New Jersey 08876-2312 (P) 908.685.0315 • (F) 908.685.0195 Email: [email protected] Prepared by: Princeton Hydro, LLC 120 East Uwchlan Avenue, Suite 204 Exton, Pennsylvania 19341 (P) 610.524.4220 • (F) 610.524.9434 Email: [email protected] February 2011 Watershed Protection and Restoration Plan for Manalapan Brook Watershed Middlesex and Monmouth Counties, New Jersey February 2011 Table of Contents Table of Contents................................................................................................................ 1 List of Tables ...................................................................................................................... 4 List of Figures..................................................................................................................... 5 Appendices.......................................................................................................................... 6 Executive Summary............................................................................................................ 8 Introduction....................................................................................................................... 10 Project Justification: ......................................................................................................... 12 Characterization and Assessment of the Watershed......................................................... 17 Introduction: ................................................................................................................. 17 Census Data: ................................................................................................................. 17 Subwatershed Delineation: ........................................................................................... 18 Land Use Land Cover: .................................................................................................. 19 Water Resource Designation: ....................................................................................... 20 Stream Network: ........................................................................................................... 22 Geology: ........................................................................................................................ 23 Soils: ............................................................................................................................. 24 Groundwater Recharge: ............................................................................................... 25 Critical Habitat: ............................................................................................................ 25 Open Space:.................................................................................................................. 27 Septic: ........................................................................................................................... 28 Impervious Surfaces: .................................................................................................... 28 Floodplains: .................................................................................................................. 29 Stream Visual Assessment Protocol ................................................................................. 30 Introduction: ................................................................................................................. 30 Delineating Assessment Stations: ................................................................................. 31 Visual Assessment Protocol: ......................................................................................... 34 Visual Assessment Data Management: ......................................................................... 36 Visual Assessment Results: ........................................................................................... 37 Water Quality Data ........................................................................................................... 47 Introduction: ................................................................................................................. 47 Sampling Protocol: ....................................................................................................... 48 In-situ Data: .................................................................................................................. 50 Temperature: ............................................................................................................. 50 Dissolved Oxygen: .................................................................................................... 51 pH: ............................................................................................................................ 54 Conductivity: ............................................................................................................. 55 Water Clarity: ........................................................................................................... 55 Discrete Parameters: .................................................................................................... 56 Total Phosphorus: ..................................................................................................... 56 Soluble Reactive Phosphorus (SRP): ........................................................................ 57 Total Suspended Solids (TSS): .................................................................................. 57 Chlorophyll a: ........................................................................................................... 58 Princeton Hydro, LLC 1 Watershed Protection and Restoration Plan for Manalapan Brook Watershed Middlesex and Monmouth Counties, New Jersey February 2011 Plankton and Fish Sampling: ........................................................................................ 59 Phytoplankton: .......................................................................................................... 59 Zooplankton: ............................................................................................................. 59 Fishery Survey: ......................................................................................................... 60 Trophic State Analyses: ................................................................................................ 61 Consecutive In-Situ Monitoring at Manalapan Lake: .................................................. 63 Discussion: .................................................................................................................... 65 Applying AVGWLF Model to Manalapan Brook Watershed.......................................... 67 Introduction: ................................................................................................................. 67 Data Requirements: ...................................................................................................... 70 Model Calibration: ....................................................................................................... 72 Model Results: .............................................................................................................. 76 Municipality Results: ................................................................................................ 77 Subwatershed Results: .............................................................................................. 80 Establishment of Targeted Endpoint and Long-Term Goal.............................................. 84 Introduction: ................................................................................................................. 84 Targeted Endpoint Analysis: ......................................................................................... 84 Watershed Protection and Restoration Implementation Strategy..................................... 86 Introduction: ................................................................................................................. 86 Project Identification and Prioritization: ..................................................................... 86 Subwatershed Ranking: ............................................................................................ 87 Land Sediment Results: ............................................................................................. 87 Streambank Erosion Results: .................................................................................... 90 Combined Subwatershed Ranking: ........................................................................... 93 Stream Visual Assessment: ....................................................................................... 95 Water Resource Protection Open Space Criteria Model (WRPOS): ........................ 95 Updated Land Use / Land Cover (LU/LC): ............................................................ 100 First Tier Project Identification and Prioritization: ............................................... 100 Second Tier Project Identification: ......................................................................... 128