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Barry R. Hill

Publications and source records attributed to Barry R. Hill.

5 recordsLinked to original sources
USGS2014

Watershed-scale modeling of streamflow change in incised montane meadows

Land use practices have caused stream channel incision and water table decline in many montane meadows of the Western United States. Incision changes the magnitude and timing of streamflow in water supply source watersheds, a concern to resource managers and downstream water users. The hydrology of montane meadows under natural and incised conditions was investigated using watershed simulation for a range of hydrologic conditions. The results illustrate the interdependence between: watershed and meadow hydrology; bedrock and meadow aquifers; and surface and groundwater flow through the meadow for the modeled scenarios. During the wet season, stream incision resulted in less overland flow and interflow and more meadow recharge causing a net decrease in streamflow and increase in groundwater storage relative to natural meadow conditions. During the dry season, incision resulted in less meadow evapotranspiration and more groundwater discharge to the stream causing a net increase in streamflow and a decrease in groundwater storage relative to natural meadow conditions. In general, for a given meadow setting, the magnitude of change in summer streamflow and long-term change in watershed groundwater storage due to incision will depend on the combined effect of: reduced evapotranspiration in the eroded meadow; induced groundwater recharge; replenishment of dry season groundwater storage depletion in meadow and bedrock aquifers by precipitation during wet years; and groundwater storage depletion that is not replenished by precipitation during wet years.

Water Resources Research↗
USGS2002

Streamflow and erosion response to prolonged intense rainfall of November 1-2, 2000, Island of Hawaii, Hawaii

A combination of several meteorologic and topographic factors produced extreme rainfall over the eastern part of the island of Hawaii on November 1-2, 2000. Storm rainfall was concentrated in two distinct areas, the Waiakea and Kapapala areas, where maximum rainfall totals of 32.47 and 38.97 inches were recorded. Resultant flooding caused damages in excess of 70 million dollars, among the highest totals associated with flooding in the State's history. Storm rainfall had recurrence intervals that ranged from 10 years or less for maximum 1-hour totals to 100 years or more for maximum 24-hour totals As part of this study, peak flow and/or erosion data were collected at 41 sites. Analyses of these data indicated that peak discharges of record occurred at 6 of 12 sites where historic data were available. Peak flows with estimated recurrence intervals from 50 to over 100 years were recorded at 4 of 11 sites. Peak flows were poorly correlated with total storm rainfall. Critical rainfall durations associated with peak flows ranged from 1 to 12 hours and were about 3 hours at most sites. Rainfall-runoff computations and field observations indicated that infiltration-excess overland flow alone was not sufficient to have caused the observed flood peaks and therefore saturation-excess overland flow and subsurface flow probably contributed to peak flows at most sites Most hillslope erosion associated with the storm took place along or near the Kaoiki Pali in the Kapapala area. Hillslope erosion was predominately caused by overland flow.

Hawaii↗
USGS1996

Streamflow and Suspended-Sediment Loads Before and During Highway Construction, North Halawa, Haiku, and Kamooalii Drainage Basins, Oahu, Hawaii, 1983-91

Concern over potential effects from construction of the H-3 highway on Oahu, Hawaii, prompted a long-term study of streamflow and suspended-sediment transport at a network of five stream-gaging stations along the highway route. This report presents results for 1983-91, which included pre-construction and construction periods at all stream-gaging stations. Annual rainfall, streamflow, and suspended-sediment loads were generally higher during construction than before construction. Data collected before and during construction were compared using analysis of covariance to determine whether streamflow and suspended-sediment loads changed significantly during construction after accounting for effects of increased rainfall. Streamflow at stream-gaging stations was compared with streamflow at an index stream-gaging station unaffected by construction. Streamflow data were divided into low- and high-flow classes, and the two flow classes were analyzed separately. Low flows increased 117 percent during construction at one station. This increase probably was related to the removal of vegetation for highway construction. Low flows decreased 28 percent at another station, probably as a result of increased ground-water withdrawals and highway construction activities. No significant changes in low flows were detected at the other stations, and no significant changes in high flows were detected at any stations. Suspended-sediment loads increased significantly during construction at three stations. Highway construction contributed between 56 and 76 percent of the suspended-sediment loads measured at these stations during construction. Loads did not change significantly at a station downstream of a reservoir, and loads decreased at a station downstream of a drainage basin that was heavily used for agriculture before construction. Suspended-sediment concentrations were used to assess compliance with applicable State water-quality standards. State water-quality standards for suspended sediment frequently were exceeded during construction. Standards occasionally were exceeded before construction.

Water-Resources Investigations Report↗
USGS1993

Geohydrology and Possible Transport Routes of Polychlorinated Biphenyls in Haiku Valley, Oahu, Hawaii

A combination of geologic mapping, seepage runs, water-budget computation, analysis of stream-gaging records, study of stream sediment, and measurement of polychlorinated biphenyls (PCBs) was used to investigate the geohydrology and possible routes of PCB transport from areas of possible contamination in the U.S. Coast Guard's Omega Station in Haiku Valley, Oahu, Hawaii. The PCBs were a contaminant in fuel that was sprayed on vegetation and ignited during defoliation efforts at the Omega Station. Haiku Valley is a stream valley eroded into a thick section of dike-intruded, highly permeable lava flows. The valley is partly filled with alluvium, pyroclastics and massive lava flows. A shallow aquifer system is formed by a permeable unit of pyroclastics which is bounded below by less permeable alluvium, massive lava flows, and weathered basalt. A deeper aquifer system is present in the dike-intruded lava flows. Much of the area of suspected PCB-contaminated fuel application in Haiku Valley is situated on the geologic unit that forms the shallow aquifer. A water budget calculated for the drainage area of a stream-gaging station (16275000) at the downgradient boundary of the Omega Station indicates that the shallow and deep aquifers receive recharge of 5.1 cubic feet per second from the 0.98 square-mile drainage area; approximately 10 percent of the drainage area is suspected to have been contaminated by PCBs. Approximately 4 cubic feet per second of water is withdrawn from the aquifers by a well and a water tunnel in the valley, but the geology of the area indicates that some of the water withdrawn by the tunnel also comes from recharge beyond the surface-water divides of Haiku Valley. Base flow to the stream is about 1.2 cubic feet per second. A water-balance calculation between recharge, well and tunnel withdrawals, and stream base flow, indicates that 1.0 cubic feet per second or more of the water recharging the drainage area may travel through the subsurface and discharge downstream beyond the limits of the Omega Station. Mass-balance calculations indicate that the concentration of PCBs that dissolves in the ground-water as it infiltrates contaminated areas will be on the order of 10-7 micrograms per liter, but these calculations are based on a number of assumptions where data are lacking. Analysis of sediment from Heeia Stream indicates that the sediment is transporting PCBs past station 16275000. Although PCB concentrations in unfiltered stream water samples collected at the station were below detection limits 0.1 micrograms per liter, PCB concentrations ranged from 64 to 230 micrograms per kilogram in suspended sediment extracted from stream water. Because most of the suspended sediment in Heeia Stream is deposited in a wetland near the coast, the potential for PCB accumulation is greatest in the wetland.

Water-Resources Investigations Report↗