Hydrologic Cycle and Physiography of Groundwater Habitats Chapter 4 Hydrologic Cycle and Physiography of Groundwater Habitats Dodds & Whiles ©2010 Elsevier, Inc.

A stream leaving a limestone cave on the South Island of New Zealand. FIGURE 4.1 A stream leaving a limestone cave on the South Island of New Zealand. ©2010 Elsevier, Inc.

FIGURE 4.2 The hydrologic cycle. ©2010 Elsevier, Inc.

Various subsurface habitats FIGURE 4.3 Various subsurface habitats ©2010 Elsevier, Inc.

FIGURE 4.4 Some equipment used for sampling soil water and groundwater. (A) A slotted well casing packed with filtering materials allows sediment-free water to be sampled. (B) A vacuum sampler (lysimeter) relies on negative pressure to extract pore water from soil. The lysimeter is put under vacuum for sampling and then put under pressure to collect the sample as it flows out of the sampling tube. ©2010 Elsevier, Inc.

piezometers can be used to determine lateral direction of flow. FIGURE 4.5 Ways to use small wells (piezometers) to estimate direction of groundwater flows. A nest (locally distributed) of piezometers can be used to determine vertical direction of flow, and spatially distributed piezometers can be used to determine lateral direction of flow. ©2010 Elsevier, Inc.

Leopold and Davis, 1996; drawn by Sarah Blair, 1998). FIGURE 4.6 Water moves through groundwater and across the surface of the land in the hydrologic cycle. (After Leopold and Davis, 1996; drawn by Sarah Blair, 1998). ©2010 Elsevier, Inc.

FIGURE 4.7 The extent of the High Plains Aquifer. In the left panel, zones of depletion .40 m depth before development to 1980 are shown in darkest colors. The most abundant gray color shows zones of no change, and the groundwater level has increased in the very light areas. In the right panel, the decline in depth between 1980 and 1997 is depicted, with the darkest colors indicating a .6 m decrease and the large gray areas indicating no significant change in depth. (Data from the US Geological Survey). ©2010 Elsevier, Inc.

FIGURE 4.8 Discharge of the Arkansas River as it flows through a region of the High Plains Aquifer that has been used heavily for center-pivot irrigation since the 1960s. The Syracuse station is immediately upstream of the High Plains Aquifer and the Dodge City station is downstream. Note that the logarithmic scale of discharge is modified so that it reads 0.01 m3 s21 when the river is dry. The river downstream of the aquifer has flowed only during periods of flooding since the early 1970s; it was almost never dry prior to that. (Data replotted from the US Geological Survey by the Central Plains Hydrologic Observatory). ©2010 Elsevier, Inc.

FIGURE 4.9 A sinkhole that formed in Bartow, Polk County, Florida. In May 22, 1967, it was 158 m long, 38 m wide, and 18 m deep. (Photograph courtesy of the US Geological Survey). ©2010 Elsevier, Inc.