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551.
Kwan Tun Lee 《Journal of the American Water Resources Association》1998,34(2):375-384
ABSTRACT: The geomorphic instantaneous unit hydrograph (GIUH) may be one of the most successful methodologies for predicting flow characteristics in ungauged watersheds. However, one difficulty in applying the GIUH model is determination of travel time, and the other difficulty is the large amount of geomorphologic information required in the study watershed. Recently, using the kinematic-wave theory Lee and Yen (1997) have analytically determined the travel times for overland and channel flows in watersheds. The limitation of using an empirical velocity equation to estimate the runoff travel time for a specified watershed is then relaxed. To simplify the time-consuming work involved in geomorphic parameter measurement on topographic maps, the GIUH model is linked with geographic information systems to obtain geomorphic parameters from digital elevation models. In this paper, a case study performed for peak flow analysis in an ungauged watershed is presented. The geomorphic characteristics of the study watershed were analyzed using a digital elevation model and were used to construct the runoff simulation model. The design storm was then applied to the geomorphic runoff simulation model to obtain the design hydrograph. The analytical procedures proposed in this study can provide a convenient way for hydrologists to estimate hydrograph characteristics based on limited hydrologic information. 相似文献
552.
Jos de Anda Sergio E. Quinones-Cisneros Richard H. French Manuel Guzmn 《Journal of the American Water Resources Association》1998,34(6):1319-1331
ABSTRACT: Lake Chapala, whose primary tributary is the Río Lerma, is the largest freshwater lake in Mexico and for the past 95 years has maintained an average storage capacity close to 6,700 Mm3. Starting hi the early 1970s, the Lerma-Chapala basin rapidly industrialized. In response to these upstream anthropogenic activities, the fisheries, aesthetics, and water quality of Lake Chapala have decreased as a consequence of the increasing chemical and biologic pollutants mainly from the Río Lerma. Additionally, the growth of Guadalajara has resulted in increasing potable water demands on the lake to satisfy a population currently greater than 4.5 million. During the 1980s, the outflow and water losses from the lake substantially exceeded the inflow and other water contributions. In this paper, the recent behavior of the hydrologic and bathymetric parameters of Lake Chapala are summarized and some important physical stresses on the system are identified. The focus of this work is the 1934–1989 period, and it is shown that starting around 1980 some of the main contributors to the lake water balance were severely perturbed and the lake reached its second lowest recorded level. The disturbances of the system are so severe that the entire regional ecosystem could be irreversibly affected in the near future. 相似文献
553.
四川省草地资源丰富,是我国五大牧区之一。本文从可持续发展理论对草地资源开发利用的指导作用、草地资源在开发利用中存在的主要问题以及如何实现草地资源开发利用的可持续发展进行了探讨 相似文献
554.
Integrating wetlands and riparian zones in river basin modelling 总被引:1,自引:0,他引:1
Wetlands, and in particular riparian wetlands, represent an interface between the catchment area and the aquatic environment. They control the exchange of water and related chemical fluxes from the upper catchment area to surface waters like streams and lakes. Their influence on water and nutrient balances has been investigated mainly at the patch scale. In this study an attempt was made (a) to integrate riparian zones and wetlands into eco-hydrological river basin modelling, and (b) to quantify the impacts of riparian wetland processes on water and nutrient fluxes in a meso-scale catchment located in the northeastern German lowland. The investigation was performed by analysing hydro-chemical field data and applying the eco-hydrological model SWIM (Soil and Water Integrated Model), which was extended to reproduce the relevant water and nutrient flows and retention processes at the catchment scale in general, and in riparian zones and wetlands in particular. The main extensions introduced in the model were: (1) implementation of daily groundwater table dynamics at the hydrotope level, (2) implementation of water and nutrient uptake by plants from groundwater in riparian zones and wetlands, and (3) assessment of nutrient retention in groundwater and interflow. The simulation results indicate that wetlands, though they represent relatively small parts of the total catchment area, may have a significant impact on the overall water and nutrient balances of the catchment. The uncertainty of the simulation results is considerably high, with the main sources of uncertainty being the model parameters representing the geo-hydrology and the input data for land use management. 相似文献
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558.
Guntenspergen GR Peterson SA Leibowitz SG Cowardin LM 《Environmental monitoring and assessment》2002,78(3):229-252
We describe a study designed to evaluate the performance ofwetland condition indicators of the Prairie Pothole Region (PPR)of the north central United States. Basin and landscape scaleindicators were tested in 1992 and 1993 to determine theirability to discriminate between the influences of grasslanddominated and cropland dominated landscapes in the PPR. Pairedplots were selected from each of the major regions of the PPR.Among the landscape scale indicators tested, those most capableof distinguishing between the two landscapes were: 1) frequencyof drained wetland basins, 2) total length of drainage ditch perplot, 3) amount of exposed soil in the upland subject to erosion,4) indices of change in area of wetland covered by water, and5) number of breeding duck pairs. Basin scale indicators includingsoil phosphorus concentrations and invertebrate taxa richnessshowed some promise; however, plant species richness was the onlystatistically significant basin scale indicator distinguishinggrassland dominated from cropland dominated landscapes. Althoughour study found a number of promising candidate indicators, oneof our conclusions is that basin scale indicators present anumber of implementation problems, including: skill levelrequirements, site access denials, and recession of site accessby landowners. Alternatively, we suggest that the use oflandscape indicators based on remote sensing can be an effectivemeans of assessing wetland integrity. 相似文献
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560.
Time Series Analysis to Monitor and Assess Water Resources: A Moving Average Approach 总被引:1,自引:0,他引:1
An understanding of the behavior of the groundwater body and its long-term trends are essential for making any management
decision in a given watershed. Geostatistical methods can effectively be used to derive the long-term trends of the groundwater
body. Here an attempt has been made to find out the long-term trends of the water table fluctuations of a river basin through
a time series approach. The method was found to be useful for demarcating the zones of discharge and of recharge of an aquifer.
The recharge of the aquifer is attributed to the return flow from applied irrigation. In the study area, farmers mainly depend
on borewells for water and water is pumped from the deep aquifer indiscriminately. The recharge of the shallow aquifer implies
excessive pumping of the deep aquifer. Necessary steps have to be taken immediately at appropriate levels to control the irrational
pumping of deep aquifer groundwater, which is needed as a future water source. The study emphasizes the use of geostatistics
for the better management of water resources and sustainable development of the area. 相似文献