The purpose of this report is to characterize the pollutant loading and restoration potential of the 46.4-acre study area mauka of the Honokōwai Beach Park (HBP), which was identified in the Wahikuli-Honokōwai Watershed Management Plan (WHWMP) as a location for a stormwater improvement project. To conduct the study, existing information on topography, streams, stormwater infrastructure, outfall locations, etc. was compiled to develop field maps delineating drainage areas and the larger HBP watershed. A field assessment of the HBP was conducted by Horsley Witten to verify the drainage network (e.g., catch basins, pipes, manholes) and identify structural and non-structural stormwater restoration alternatives on public and private property. Primary conclusions from the field investigation include:
This study illustrates the complexity of watershed planning along an intensely-developed coastline where:
This study demonstrates the level of effort that can be required to fully understand the magnitude of runoff issues and illuminate the challenges of successful watershed restoration.
Citation: Horsley Witten Group, Inc. (2016). Honokōwai Water Quality Management Plan. Prepared for National Oceanic and Atmospheric Administration's Coral Reef Conservation Program. Horsley Witten Group, Inc., Sandwich, MA. 69 p.