| Abstract: | Waiawa shaft is a 1,700-foot long water tunnel which draws water from the top of the Pearl Harbor Ghyben-Herzberg ground-water lens, Oahu, Hawaii. The application of brackish irrigation water to sugarcane fields overlying Waiawa shaft, combined with relatively low pumping rates at the shaft from 1978 to 1980, caused the chloride concentration of water produced by Waiawa shaft to rise to 290 milligrams per liter. Time-series analyses, pumping tests and analyses of water samples show that a zone of degraded water lies at the top of the lens. This zone is mixed in significantly different proportions with the underlying fresher water depending on the pumping rate at Waiawa shaft. The chloride concentration of water in the Waiawa shaft can generally be kept below 250 milligrams per liter for the next few years, if pumping rates of about 15 million gallons per day are maintained. The use of managed pumping to control the chloride problem over the long term is uncertain owing to the possible increase in chloride concentration of the irrigation water. Based on ground-water flow rates and analogy to nearby wells, the chloride concentration of Waiawa shaft ‘s water will decrease to less than 100 milligrams per liter in 2 to 3 years if the use of brackish irrigation water is discontinued. (USGS) |
| Genre: | USGS Numbered Series |
| ProdID: | 27012 |
| Citation Author: | Eyre, P. R. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | v, 49 p. :ill., maps ;28 cm. |
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| Citation Publisher: | U.S. Geological Survey, |
| Citation Series: | Water-Resources Investigations Report |
| Citation Series Code: | WRI |
| Citation Series Number: | 83-4097 |
| Citation Search Results Text: | The effects of pumpage, irrigation return, and regional ground-water flow on the water quality at Waiawa water tunnel, Oahu, Hawaii; 1983; WRI; 83-4097; Eyre, P. R. |
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| Citation Year: | 1983 |
| Type: | citation/reference |
| Text: | The effects of pumpage, irrigation return, and regional ground-water flow on the water quality at Waiawa water tunnel, Oahu, Hawaii; 1983; WRI; 83-4097; Eyre, P. R. |
| URL (THUMBNAIL): | http://pubs.usgs.gov/wri/1983/4097/report-thumb.jpg |
| URL (DOCUMENT): | http://pubs.usgs.gov/wri/1983/4097/report.pdf |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | U.S. Geological Survey, |
