West Honolulu Watershed Study
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West Honolulu Watershed Study Final Report Prepared For: Honolulu Board of Water Supply Department of Land and Natural Resources, Engineering Division U.S. Army Corps of Engineers, Honolulu District Prepared By: Townscape, Inc. and Eugene P. Dashiell, AICP May 2003 West Honolulu Watershed Study - Final Report - Prepared for: HONOLULU BOARD OF WATER SUPPLY DEPARTMENT OF LAND AND NATURAL RESOURCES ENGINEERING DIVISION U.S. ARMY CORPS OF ENGINEERS HONOLULU DISTRICT Prepared by: Townscape, Inc. and Eugene P. Dashiell, AICP May 2003 This page intentionally left blank. West Honolulu Watershed Study FINAL REPORT WEST HONOLULU WATERSHED STUDY ACKOWLEDGEMENTS This study was conducted under the direction of the U.S. Army Corps of Engineers, Honolulu District (COE), through Section 22 of the Water Resources Development Act of 1974, as amended. Project manager for the West Honolulu Watershed Study was Derek Chow of COE, Engineer District, Honolulu. Local sponsorship for the study was provided jointly by the City and County of Honolulu Board of Water Supply, represented by Barry Usagawa, Principal Executive of the Water Resources Unit, and Scot Muraoka, Long-Range Planning Section; and the State of Hawaiÿi Department of Land and Natural Resources (DLNR), Engineering Division, which was represented by Sterling Yong, Head of the Flood Control and Dam Safety Section, and Eric Yuasa and Carty Chang of the Project Planning Section. The three co-sponsors of this study wish to acknowledge the following groups and individuals for their contribution to the West Honolulu Watershed Study: Principal Planner and President Bruce Tsuchida and Staff Planners Michael Donoho and Sherri Hiraoka of Townscape, Inc., contracted through the COE as the planning consultant for the study. Water resource specialist Eugene Dashiell performed a sub-consultant role in this effort. All agencies that agreed to participate and share information in the consultation phase of this process, including Steve Anthony and Barry Hill of the U.S. Department of the Interior, Geological Survey; Bruce Anderson, June Harrigan, and Ed Chen of the State of Hawaiÿi Department of Health; Wendy Wiltse of the U.S. Environmental Protection Agency; Kathleen Dobler, Chris Smith, Doug Toews, and Terrell Kelley of the U.S. Department of Agriculture, Natural Resources Conservation Service; Gerald Takayesu of the City and County of Honolulu Department of Environmental Services; Glenn Oyama and Chester Lao of the City and County of Honolulu Board of Water Supply; Annette Tagawa and Mike Yamamoto of DLNR, Division of Aquatic Resources; Pat Costales and Aaron Lowe of DLNR, Division of Forestry and Wildlife; David Higa of DLNR, Commission on Water Resource Management; Tim Johns of the Damon Estate; Manabu Tagomori of the Kamehameha Schools and the Koÿolau Mountain Watershed Partnership; Dr. Dieter Mueller-Dombois of the University of Hawaiÿi (UH) Department of Botany; Dr. Aly El-Kadi of the UH Water Resources Research Center; Charlotte Yamane, Bill Gorst, and Patrick Rorie of the Hawaiÿi Trail and Mountain Club; and the many others who provided information and insights about the West Honolulu Watershed. i West Honolulu Watershed Study FINAL REPORT WEST HONOLULU WATERSHED STUDY TABLE OF CONTENTS PAGE Acknowledgements.................................................................................................................... i Table of Contents...................................................................................................................... ii List of Acronyms ..................................................................................................................... iv Executive Summary.................................................................................................................. v SECTION 1. WEST HONOLULU WATERSHED STUDY OVERVIEW 1.1 Purpose 1 1.2 Objectives……………………………………………………...……....... 2 1.3 Study Sponsors and Methodology ............................................................ 2 1.4 Agencies Consulted…………………………………………………....... 3 SECTION 2. WEST HONOLULU WATERSHED STUDY PROJECT AREA 2.1 Physical Description.................................................................................. 5 2.2 Urban District............................................................................................11 2.3 Conservation District ................................................................................13 2.4 West Honolulu Watershed Area Sub-Watersheds ....................................14 2.5 Historic Conditions ...................................................................................19 SECTION 3. DATA INVENTORY, CRITICAL ISSUES, AND GUIDING PRINCIPLES 3.1 Description of Available Written Materials..............................................29 3.2 Summary of Findings and Recommendations from Technical Reports ...30 3.3 Gaps in the Data Record ..........................................................................33 3.4 Summary of Critical Issues .......................................................................34 3.5 “Guiding Principles” .................................................................................42 3.6 The Ahupuaÿa Concept .............................................................................46 SECTION 4. DESCRIPTION OF RECOMMENDED PROJECTS 4.1 WHWS Recommendations .......................................................................49 4.2 Detailed Project Descriptions....................................................................50 ii West Honolulu Watershed Study FINAL REPORT WEST HONOLULU WATERSHED STUDY TABLE OF CONTENTS PAGE FIGURES 2.1 Study Area..............................................................................................10 2.2 Neighborhood Boards ............................................................................12 2.3 Kona District, Oÿahu Island, circa 1959.................................................20 2.4 Historic Conditions, Circa 1902.............................................................28 3.1 Generalized Flooding .............................................................................37 3.2 Large Parcel Ownership.........................................................................39 4.1 Proposed Projects ...................................................................................53 TABLES 1.1 Agencies Consulted During the West Honolulu Watershed Study........ 4 2.1 BWS Sustainable Yields for WHW Aquifers ........................................ 6 2.2 Kalihi Fishponds ....................................................................................22 2.3 Kapälama Fishponds ..............................................................................23 2.4 Nuÿuanu Fishponds ................................................................................24 3.1 Trace Element and Inorganic Carbon Concentrations in Streambed Sediment.................................................................................................36 3.2 Major Landowners by Ahupuaÿa............................................................38 APPENDICES A. West Honolulu Watershed Study Comprehensive Bibliography B. Summaries of Selected Studies and Data Reports C. Agency Profiles and Watershed Programs D. Sources of Government Funding iii West Honolulu Watershed Study FINAL REPORT LIST OF ACRONYMS USED BMP Best management practice BWS Honolulu Board of Water Supply CCH City and County of Honolulu CFS Cubic feet per second COE U.S. Army Corps of Engineers (Federal) CPRD Coastal Protection and Restoration Division (NOAA) CRM Concrete, rubble, masonry CWB Clean Water Branch (DOH) CWP Center for Watershed Protection CWRM Commission on Water Resource Management (State) CZARA Coastal Zone Act Reauthorization Amendments CZMP Coastal Zone Management Program (State) DAR Division of Aquatic Resources (DLNR) DDC Department of Design and Construction (CCH) DFM Department of Facilities Maintenance (CCH) DLNR Department of Land and Natural Resources (State) DOFAW Division of Forestry and Wildlife (DLNR) DOH Department of Health (State) DOT Department of Transportation (State) DPP Department of Planning and Permitting (CCH) DWSRF Drinking Water State Revolving Fund EIS Environmental Impact Study ENV Department of Environmental Services (CCH) EPA Environmental Protection Agency (Federal) GWPP Ground Water Protection Program HTMC Hawaiÿi Trail and Mountain Club KMWP Koÿolau Mountains Watershed Partnership MGD Million gallons per day NAWQA National Water Quality Assessment (USGS) NDPES National Pollutant Discharge Elimination System NOAA National Oceanic and Atmospheric Administration NRCS Natural Resource Conservation Service (USDA) SCS Soil Conservation Service (USDA NRCS) TMDL Total Maximum Daily Load TNC The Nature Conservancy UH University of Hawaiÿi USDA United States Department of Agriculture (Federal) USFS United States Forest Service (USDA) USFWS United States Fish & Wildlife Service (Federal) USGS United States Geological Survey (Federal) WHW West Honolulu Watershed WHWS West Honolulu Watershed Study WRRC Water Resources Research Center (UH) iv West Honolulu Watershed Study FINAL REPORT WEST HONOLULU WATERSHED STUDY EXECUTIVE SUMMARY Study Objective: To provide a holistic, comprehensive analysis of watershed data, problems and issues and to conceptualize and describe potential watershed restoration projects and actions. Important distinction: this watershed analysis is a study; it is not a “watershed plan” that prescribes a sequence of