Finstick, Sue A. 1998.
Project Report PR-99-05, Water Resources Research Center, University of Hawai'i at Manoa, Honolulu. 225 pp.
Mitigating the harmful effects of development projects and industries (negative environmentalism) is inadequate, especially in resource-dependent economies whose resources are at risk from other forces. While positive environmentalism includes conservation projects, the non-market benefits of such projects are difficult to evaluate. This paper provides and illustrates a method for evaluating the indirect, watershed benefits of a tropical forest, without resorting to survey -methods. The conservation of trees prevents a reapportionment from groundwater recharge to runoff that would otherwise occur. The value of the water saved is then valued at the shadow prices obtained from an optimizing model. An illustration of the model shows that watershed conservation projects may have very high payoffs, even before assessing existence values and other forest amenities.
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.