Please use this identifier to cite or link to this item:

WRRCPR No.99-05 Subsurface geology and hydrogeology of downtown Honolulu, with engineering and environmental implications

File Size Format  
WRRCPR99-05.pdf 13.08 MB Adobe PDF View/Open

Item Summary

Title:WRRCPR No.99-05 Subsurface geology and hydrogeology of downtown Honolulu, with engineering and environmental implications
Authors:Finstick, Sue A.
Keywords:subsurface mapping
engineering geology
subsurface geology
subsurface hydrology
show 4 moreenvironmental implications
downtown Honolulu
show less
LC Subject Headings:Engineering geology -- Hawaii -- Oahu.
Honolulu (Hawaii)
Hydrogeology -- Hawaii -- Oahu.
Tall buildings -- Design and construction -- Hawaii -- Oahu.
Date Issued:Oct 1998
Publisher:Water Resources Research Center, University of Hawaii at Manoa
Citation:Finstick SA. 1998. Subsurface geology and hydrogeology of downtown Honolulu, with engineering and environmental implications. Honolulu (HI): Water Resources Research Center, University of Hawaii at Manoa. WRRC project report, 99-05.
Series:WRRC Project Report
Abstract:In the downtown Honolulu area, detailed site investigations are required prior to the design and construction of high-rise buildings and other engineering structures. Hence, over the years, numerous soil borings, environmental assessments, and groundwater measurements have been conducted. As a result, much data on the subsurface geology of downtown Honolulu exists, but it is spread out among individual consulting firms and various governmental agencies. The purpose of this study is to compile the existing data and interpret the subsurface geology, engineering geology, hydrogeology, and environmental problems within the downtown Honolulu area. This study commenced with collecting and interpreting data from 2,276 soil boring logs from consulting firms in Honolulu, along with data from the Groundwater Index database and environmental databases maintained by the State of Hawaii. The subsurface materials are classified into nine categories: fill, lagoonal (low-energy) deposits, alluvial deposits, coralline debris, coral ledges, cinders, tuff, basalt, and residual soil or weathered volcanics. The study area is divided into 157 quadrangles (1,000 feet x 1,000 feet each). The subsurface conditions within each quad are described in detail, and nine cross-sections are presented for further clarification of the subsurface geology. Foundation-bearing layers and buried alluvial channels are mapped. Environmental problems and groundwater data are summarized in tables and maps. Coral ledges, tuff, and basalt are the most suitable foundation-bearing layers within the caprock. Coral ledges, coralline debris, coarse-grained lagoonal sediments, and cinder sands are characterized by higher hydraulic conductivities than other materials that comprise the caprock. However, the caprock as a whole is characterized by much lower hydraulic conductivities than the underlying Koolau basalt that forms the main aquifer for the island. The caprock groundwater is not only brackish and nonpotable but also highly vulnerable to contamination. Petroleum hydrocarbons and heavy metals from leaking underground storage tanks are the primary soil and groundwater contaminants. Caprock groundwater is generally found within ±5 feet of sea level. Dewatering is often necessary at sites involving the construction of basements.
Pages/Duration:xii + 225 pages
Appears in Collections: WRRC Project Reports

Please email if you need this content in ADA-compliant format.

Items in ScholarSpace are protected by copyright, with all rights reserved, unless otherwise indicated.