Instream Flow Standard Assessment Report Island of Maui Hydrologic Unit 6052 Nuaailua December 2009 PR-2009-06
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Instream Flow Standard Assessment Report Island of Maui Hydrologic Unit 6052 Nuaailua December 2009 PR-2009-06 State of Hawaii Department of Land and Natural Resources Commission on Water Resource Management COVER Nuaailua Stream flows to the rocky coastline and empties into Nuaailua Bay [Google Earth, 2009]. Note: This report is intended for both print and electronic dissemination and does not include diacritical marks in spelling of Hawaiian words, names, and place names due to problems associated with its use electronically. However, Commission staff has made attempts to include diacritical marks in direct quotations to preserve accuracy. Table of Contents 1.0 Introduction......................................................................................................... 1 1.1 General Overview...........................................................................................................................1 1.2 Current Instream Flow Standard ..................................................................................................1 1.3 Instream Flow Standards ..............................................................................................................1 1.4 Interim Instream Flow Standard Process ....................................................................................2 1.5 Instream Flow Standard Assessment Report .............................................................................3 1.6 Surface Water Hydrologic Units ...................................................................................................4 1.7 Surface Water Definitions .............................................................................................................4 2.0 Unit Characteristics.......................................................................................... 10 2.1 Geology.........................................................................................................................................10 2.2 Soils...............................................................................................................................................11 2.3 Rainfall ..........................................................................................................................................12 2.4 Solar Radiation.............................................................................................................................14 2.5 Evaporation ..................................................................................................................................14 2.6 Land Use .......................................................................................................................................15 2.7 Land Cover ...................................................................................................................................15 2.8 Flood..............................................................................................................................................16 2.9 Drought .........................................................................................................................................17 3.0 Hydrology.......................................................................................................... 26 3.1 Streams in Hawaii ........................................................................................................................26 3.2 Ground Water ...............................................................................................................................26 3.3 Streamflow Characteristics.........................................................................................................29 3.4 Long-Term Trends in Streamflow...............................................................................................31 4.0 Maintenance of Fish and Wildlife Habitat....................................................... 36 4.1 Impacts on Native Species Distribution ....................................................................................37 4.2 Brief Overview of Literature........................................................................................................39 4.3 Analysis of Habitat Availability...................................................................................................40 4.4 Distribution of Native Freshwater Species................................................................................43 4.5 Other Critical Habitats .................................................................................................................46 5.0 Outdoor Recreational Activities...................................................................... 50 6.0 Maintenance of Ecosystems............................................................................ 54 7.0 Aesthetic Values............................................................................................... 62 8.0 Navigation ......................................................................................................... 64 9.0 Instream Hydropower Generation................................................................... 65 10.0 Maintenance of Water Quality ......................................................................... 67 11.0 Conveyance of Irrigation and Domestic Water Supplies .............................. 72 12.0 Protection of Traditional and Customary Hawaiian Rights........................... 73 13.0 Noninstream Uses ............................................................................................ 94 13.1 Stream Diversions........................................................................................................................94 13.2 Ground Water Recharge............................................................................................................101 13.3 Classification of Agricultural Lands ........................................................................................103 i 13.4 East Maui Irrigation System......................................................................................................103 13.4.1 System Overview.................................................................................................................103 13.4.2 History of Water Licenses ...................................................................................................106 13.4.3 Hawaiian Commercial and Sugar Company .......................................................................110 Sugar Production.................................................................................................................110 Energy Production...............................................................................................................111 Water Use............................................................................................................................112 Economic Impact.................................................................................................................118 13.4.4 Maui Land and Pineapple Company ...................................................................................120 Water Use............................................................................................................................120 Economic Impact.................................................................................................................121 13.4.5 Kula Agricultural Park..........................................................................................................121 Water Use............................................................................................................................122 Economic Impact.................................................................................................................123 13.4.6 County of Maui, Department of Water Supply.....................................................................123 Water Use............................................................................................................................124 Economic Impact.................................................................................................................124 13.5 County of Maui, Department of Water Supply Upcountry System .......................................125 13.5.1 System Overview.................................................................................................................125 13.5.2 System Users ......................................................................................................................127 13.5.3 Water Use............................................................................................................................128 Historical and Current Uses ................................................................................................128 Future Demands..................................................................................................................131 13.5.4 Economic Impact.................................................................................................................132 14.0 Bibliography.................................................................................................... 138 15.0 Appendices ..................................................................................................... 151 ii List of Figures Figure 1-1. Information to consider in setting measurable instream