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Water Features (water + feature)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

A comparative analysis of the habitat of the extinct aurochs and other prehistoric mammals in Britain

ECOGRAPHY, Issue 2 2008
Stephen J. G. Hall
The present study tests the hypothesis that the habitat of the globally extinct aurochs Bos primigenius was primarily riverine flat-lands. Landscape features in Britain were analyzed for sites with Late Pleistocene and postglacial finds of aurochs (n=188), and, for comparison, wolf (101), brown bear (96), red deer (73), beaver (68), roe deer (46) and moose (23). Find sites were defined as Ordnance Survey 1 km map squares containing 1 or more finds. For each, spot height above sea level, heights of contour lines, flatness of terrain, total length of watercourses, and presence of woods, rock and water features were noted. Comparisons of find sites among species (Kruskal-Wallis test) show significant differences that accord with knowledge of present-day habitat preferences at the landscape level. Considering the species separately each find site was then compared with a randomly selected control map square within 10 km. Compared with their respective control squares, find sites of beaver have, today, a stronger association with presence of lakes; those of brown bear and wolf with presence of cliffs and rock outcrops; and those of aurochs with absence of woodland and with lower elevation and greater flatness. The concordance of these findings with the present-day habitats of the extant species suggests valid inferences can be made about the habitat preference of the extinct aurochs. On this basis the aurochs appears, as hypothesized, to have selected low-lying, flat ground, which (indicated by its present-day use for purposes other than woodland) was relatively fertile. [source]

Ground Water Flow Analysis of a Mid-Atlantic Outer Coastal Plain Watershed, Virginia, U.S.A.

GROUND WATER, Issue 2 2002
Michael A. Robinson
Models for ground water flow (MODFLOW) and particle tracking (MODPATH) were used to determine ground water flow patterns, principal ground water discharge and recharge zones, and estimates of ground water travel times in an unconfined ground water system of an outer coastal plain watershed on the Delmarva Peninsula, Virginia. By coupling recharge and discharge zones within the watershed, flowpath analysis can provide a method to locate and implement specific management strategies within a watershed to reduce ground water nitrogen loading to surface water. A monitoring well network was installed in Eyreville Creek watershed, a first-order creek, to determine hydraulic conductivities and spatial and temporal variations in hydraulic heads for use in model calibration. Ground water flow patterns indicated the convergence of flow along the four surface water features of the watershed; primary discharge areas were in the noontide portions of the watershed. Ground water recharge zones corresponded to the surface water features with minimal development of a regional ground water system. Predicted ground water velocities varied between < 0.01 to 0.24 m/day, with elevated values associated with discharge areas and areas of convergence along surface water features. Some ground water residence times exceeded 100 years, although average residence times ranged between 16 and 21 years; approximately 95% of the ground water resource would reflect land use activities within the last 50 years. [source]

RECIRCULATING WELLS: GROUND WATER REMEDIATION AND PROTECTION OF SURFACE WATER RESOURCES,

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2000
Keith W. Ryan
ABSTRACT: Several chlorinated solvent plumes threaten the sole-source aquifer underlying the Massachusetts Military Reservation at the western end of Cape Cod. Sensitive surface water features including ponds, cranberry bogs, and coastal wetlands are hydraulically connected to the aquifer. For one of the plumes (CS-10 the original remedy of 120 extraction and reinjection wells has the potential for significant disruption of surface water hydrology, through the localized drawdown and mounding of the water table. Recirculating wells with in-well air stripping offer a cost-effective alternative to conventional pump-and-treat technology that does not adversely affect the configuration of the water table. Pilot testing of a two well system, pumping 300 gpm, showed a capture radius of > 200 feet per well, in-well trichloroethylene (TCE) removal efficiencies of 92 to 98 percent per recirculation cycle, an average of three recirculation cycles within the capture zone, and no measurable effect on water table elevations at any point within the recirculation/treatment zone. During 120 days of operation, the mean concentration of TCE in the treatment zone was reduced by 83 percent, from 1,111 ,g/l to 184 ,g/l. Full-scale design projections indicate that 60 wells at an average spacing of 160 feet, having an aggregate recirculation 11 MGD, can contain the CS-b plume without ground water extraction or adverse hydraulic effects on surface water resources. The estimated capital costs for such a system are about $7 million, and annual operations-and-maintenance costs should be about $1.4 million, 40 percent of those associated with a pump and treat system over a 20-year period. [source]

Groundwater Systems and Eco-hydrological Features in the Main Karst Regions of China

ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 5 2006
LU Yaoru
Abstract: Different karst water features and related water resources are present both in southern and northern China. There are over 3,358 well-developed karst ground river systems with total discharges in the dry season of about 420times108 m3 in the main karst regions in the southern part of China. Exploitation rates are only 8,15%. Over 100 larger karst spring systems in the main karst regions of northern China cover a catchment area from 500 km2 to over 4,000 km2, of which the average discharge appears to be from about 1 m3/s to 13 m3/s and the exploitation rates are 70,80%. Six aspects of the eco-hydrological features of some typical karst regions in China comprising water environment, ecological features, materials and structures between parent rock and soil, bio-geological processes and palynological studies (spore-pollen) are discussed. Qualitative evaluation of eco-geology and rocky desertification in the karst regions should be based on the main karst ecological conditions as well as artificial, i.e., man-made impacts. [source]