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1.
Agricultural water management (AWM) is the adaptation strategy for increasing agricultural production through enhancing water resources availability while maintaining ecosystem services. This study characterizes groundwater hydrology in the Kothapally agricultural watershed, in hard rock Deccan plateau area in India and assesses the impact of AWM interventions on groundwater recharge using a calibrated and validated hydrological model, SWAT, in combination with observed water table data in 62 geo‐referenced open wells. Kothapally receives, on average, 750 mm rainfall (nearly 90% of annual rainfall) during the monsoon season (June to October). Water balance showed that 72% of total rainfall was converted as evapotranspiration (ET), 16% was stored in aquifer, and 8% exported as runoff from the watershed boundary with AWM interventions. Nearly 60% of the runoff harvested by AWM interventions recharged shallow aquifers and rest of the 40% increased ET. Water harvesting structures (WHS) contributed 2.5 m additional head in open wells, whereas hydraulic head under natural condition was 3.5 m, resulting in total 6 m rise in water table during the monsoon. At the field scale, WHSs recharged open wells at a 200 to 400 m spatial scale.  相似文献   

2.
The contradiction between the freshwater shortage and the large demand of freshwater by irrigation was the key point in cultivated lowland area of North China Plain. Water transfer project brings fresh water from water resource‐rich area to water shortage area, which can in turn change the hydrological cycle in this region. Major ions and stable isotopes were used to study the temporal variations of interaction between surface water and groundwater in a hydrological year after a water transfer event in November 2014. Irrigation canal received transferred Yellow River, with 2.9% loss by evaporation during water transfer process. The effect of transferred water on shallow groundwater decreased with increasing distance from the irrigation canal. Pit pond without water transfer receives groundwater discharge. During dry season after water transfer event, shallow groundwater near the irrigation canal was recharged by lateral seepage and deep percolation of irrigation, whereas shallow groundwater far from irrigation canal was recharged by deep percolation of deep groundwater irrigation. Canal water lost by evaporation was 2.7–17.4%. Influence of water transfer gradually disappeared until March as the water usage of agricultural irrigation increased. In the dry season, groundwater discharged to irrigation canal and pond; 2.2–31.6% canal water and 11.3–20.0% pond water were lost by evaporation. In the rainy season (June to September), surface water was fed mainly by precipitation and surface run‐off, whereas groundwater was recharged by infiltration of precipitation. The two‐end member mix model showed that the mixing ratio of precipitation in pond and irrigation canal were 73–83.4% (except one pond with 28.1%) and 77.3–99.9%, respectively. Transferred water and precipitation were the important recharge sources for shallow groundwater, which decreased groundwater salinity in cultivated lowland area of North China Plain. With the temporary and spatial limitation of water transfer effects, increased water transfer amounts and frequency may be an effective way of mitigating regional water shortage. In addition, reducing the evaporation of surface water is also an important way to increase the utilization of transfer water.  相似文献   

3.
Seasonally variation of water salinity is observed worldwide, the mechanisms of water salinity are not well understood due to natural factors and anthropogenic activities. Quantification water salinity source are challenging since complex influence factors, especially in agricultural regions irrigated with multi-water sources. In the lowland area of North China Plain, transferred water, brackish shallow groundwater and fresh deep groundwater were combinative utilized to relieve prominent contradictions between regional water shortages and grain production. In this study, influence factors of surface water (canal water, pond water) and shallow groundwater salinity were identified and quantified through statistical analysis, deuterium excess, and ionic relationship. Salinity of canal water and pond water increased in dry season and decreased in rainy season, while salinity of shallow groundwater decreased in dry season after water transfer and rainy season, but increased in dry season. Evaporation and mineral dissolution were main factors for surface water salinity in dry season, with mineral dissolution was the more important one. The contribution ratio of evaporation and mineral dissolution for canal salinity were 4.4 and 49.1% in dry season after water transfer, 7.1 and 34.4% in dry season, and that for pond water salinity were 12.4 and 18.3% in dry season, respectively. Precipitation and surface runoff were main factors for surface water salinity in rainy season. The contribution of surface runoff for canal water and pond water salinity were 66.1 and 45.8%, respectively. Salinity of canal water and shallow groundwater was temporary decreased by water transfer. Domestic sewage from rural areas had larger influence than agricultural activities for salinity increase of pond water and shallow groundwater. Mineral dissolution was the main contributor for shallow groundwater salinity, with contribution ratio larger than 60% in different periods. This study demonstrated and quantified salinity source of surface water and shallow groundwater and may deepen our understanding of water management under multi-water resources utilization.  相似文献   

4.
The aim of this study was to display distribution and relationships of heavy elements in the unconfined, shallow alluvial aquifers of the lower Jia Bharali catchment and adjoining areas in central part of North Brahmaputra Plain (NBP), India using hydrochemical as well as multivariate statistical techniques such as principal component analysis (PCA) and cluster analysis. The original matrix was made up of 10 trace elements (As, Cd, Cu, Co, Cr, Fe, Mn, Pb, Ni and Zn) estimated from 50 shallow alluvial dug wells in both the wet and the dry season for a duration of 3 hydrological years (2008–2011). Except As, Cu and Zn all the other toxic metals in the shallow aquifers were found exceeding the WHO maximum permissible limits for drinking water. PCA extracted five varimax factors as geogenic, agricultural and anthropogenic explaining about 71.2% of the total variance in the wet season and 69.3% total variance in the dry season. Hierarchical cluster analysis classified the dug wells into two groups in the wet season and three groups in the dry season with respect to the heavy elements. The results emphasized the need for routine monitoring and management in order to avoid contamination of groundwater sources in the NBP with respect to the dissolved trace elements.  相似文献   

5.
Mountainous areas are characterized by steep slopes and rocky landforms, with hydrological conditions varying rapidly from upstream to downstream, creating variable interactions between groundwater and surface water. In this study, mechanisms of groundwater–surface water interactions within a headwater catchment of the North China Plain were assessed along the stream length and during different seasons, using hydrochemical and stable isotope data, and groundwater residence times estimated using chlorofluorocarbons. These tracers indicate that the river is gaining, due to groundwater discharge in the headwater catchment both in the dry and rainy seasons. Residence time estimation of groundwater using chlorofluorocarbons data reveals that groundwater flow in the shallow sedimentary aquifer is dominated by the binary mixing of water approximating a piston flow model along 2 flow paths: old water, carried by a regional flow system along the direction of river flow, along with young water, which enters the river through local flow systems from hilly areas adjacent to the river valley (particularly during the rainy season). The larger mixing ratio of young water from lateral groundwater recharge and return flow of irrigation during the rainy season result in higher ion concentrations in groundwater than in the dry season. The binary mixing model showed that the ratio of young water versus total groundwater ranged from 0.88 to 0.22 and 1.0 to 0.74 in the upper and lower reaches, respectively. In the middle reach, meandering stream morphology allows some loss of river water back into the aquifer, leading to increasing estimates of the ratio of young water (from 0.22 to 1). This is also explained by declining groundwater levels near the river, due to groundwater extraction for agricultural irrigation. The switch from a greater predominance of regional flow in the dry season, to more localized groundwater flow paths in the wet season is an important groundwater–surface water interactions mechanism, with important catchment management implications.  相似文献   

6.
Arsenic in groundwater has been a concern in South and Southeast Asia for more than a decade. We explore here the possibility that hydrogeologic factors recently shown to influence the distribution of arsenic might also affect the level of contamination of shallow (<20 m) wells with microbial pathogens. A total of 96 shallow tube wells in two nearby villages of Bangladesh were surveyed during the wet and dry seasons, along with 55 deeper wells in neighboring villages. One of the two villages is located in a particularly sandy environment where recharge is rapid and shallow wells contain little arsenic. Shallow aquifers in the other village are capped with an impermeable clay layer, recharge is an order of magnitude slower, and arsenic levels are high. The fecal indicator E. coli was detected in 43% of shallow wells, compared with 12% of deeper wells. More shallow wells contained E. coli during the wet season (61%) than during the dry season (9%). In the wet season, a higher proportion of shallow wells in the village with low arsenic levels (72%) contained E. coli compared with the village having high arsenic levels (43%). Differences in arsenic and E. coli distributions between the two sites are likely due to the differences in permeability of near‐surface sediments although differences in average well‐depth between the two villages (9 ± 4 vs. 15 ± 3 m) may play a role as well. Hydrogeologic conditions that favor high levels of fecal contamination but low levels of arsenic in shallow groundwater should be taken into account during arsenic mitigation throughout South and Southeast Asia.  相似文献   

7.
Understanding anthropogenic impacts on water storage and water flow pathways in catchments is an ongoing challenge in hydrology. Here, we study the dynamics of subsurface storage and residence time of water in a catchment in Berkeley, California, that is within a regional park but contains diverse land use within its perimeter, including a periodically irrigated golf course. Our study combines several isotopic tracers with water budget data to examine sources of water in a stream draining the site. Irrigation water, applied to a small area of the watershed, is a minor component of the water budget. However, geochemical tracers reveal that irrigation water is a significant fraction of stream flow downstream of the golf course during baseflow and during precipitation events. Isotopic tracers indicate that the watershed has a preference to release young water for stream flow generation, resulting in contrasting tritium ages for stream water and groundwater of 1.3 ± 0.5 year and 8.2 ± 1.7 year, respectively. We determined that the older water is a very small component (0.7%) of the stream water in the tail of an assumed exponential distribution. We used the seasonal variation of stable water isotopes in precipitation and stream water over two water years to explain the damping of the isotopic signature of stream water, which yields information about the catchment's response to the input signal. The methods described here may be applicable to other urban or suburban headwater catchments in areas with a component of non-natural recharge from, for example, leaky infrastructure, storm water routing or dry season irrigation.  相似文献   

8.
Numerical groundwater flow models necessarily are limited to subsurface flow evaluation. It is of interest, however, to examine the possibility that, for unconfined aquifer systems, they could be used to proportionately measure the magnitude of seepage they estimate when these aquifers intersect the landscape surface. Our goal in this study was to determine the degree to which an unconfined groundwater model can estimate run‐off or seepage at the land surface during winter time wet season conditions, as well as in the dry season, when evapotranspiration is a major part of the water balance, using a lowland basin‐fill example study area in the Pacific Northwest. The exit gradient is a metric describing the potential for vertical seepage at the landscape surface. We investigated the spatial relationship of mapped surface features, such as wetlands, streams and ponds, to the model‐predicted mapped exit gradient. We found that areas mapped as wetlands had positive exit gradients. During the wet season, modelled exit gradients predicted seepage throughout extensive areas of the groundwater shed, extending far beyond mapped wetland areas (355% increase), associated with previously observed increases in nitrate‐nitrogen in streams in wet season. During the dry season, exit gradients spatially corresponded with wetland areas. The increase in in‐stream nitrogen corresponds with shorter residence times in carbon‐rich wetland zones because of the onset of saturation overland flow. We present results that suggest that the exit gradient could be a useful concept in examining the groundwater–surface water linkage that is often under represented physically in watershed flow models. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.  相似文献   

9.
A combination of micro-meteorological, soil physical and groundwater chemical methods enabled the water balance of a tropical eucalypt savanna ecosystem in Northern Australia to be estimated. Heat pulse and eddy correlation were used to determine overstory and total evapotranspiration, respectively. Measurements of soil water content, matric suction and water table variations were used to determine changes in soil moisture storage throughout the year. Groundwater dating with chlorofluorocarbons was used to estimate net groundwater recharge rates, and stream gauging was used to determine surface runoff. The wet season rainfall of 1585 mm is distributed as: evapotranspiration 810 mm, surface runoff (and shallow subsurface flow) into the river 410 mm, groundwater recharge 200 mm and increase in soil store 165 mm. Of the groundwater recharge, 160 mm enters the stream as baseflow in the wet season, 20 mm enters as baseflow in the dry season, and the balance (20 mm) is distributed to and used by minor vegetation types within the catchment or discharges to the sea. In the dry season, an evapotranspiration of 300 mm comprises 135 mm rainfall and 165 mm from the soil store. Because of the inherent errors of the different techniques, the water balance surplus (estimated at 20 mm) cannot be clearly distinguished from zero. It may also be as much as 140 mm. To our knowledge, this is the first time that such diverse methods have been combined to estimate all components of a catchment's water balance.  相似文献   

10.
The water balance of a 600 m2 field site on a lateritic hillslope in Kerala, southwest India, has been studied during two southwest monsoon seasons. Surface runoff was of minor importance while infiltration and evapotranspiration were the major components amounting to approximately 2/3 and 1/3 of the rainfall, respectively. Groundwater response was rapid, involving fluctuations of several metres. Recharge mechanisms hypothesized are water movement via preferred pathways from the ground surface to the capillary fringe where rapid rise in groundwater level is brought about by a transmitted pressure pulse. Groundwater recharge was found normally to take place during the southwest monsoon season only. the field study demonstrates that seasonal shallow groundwater recharge representing the major portion of the rainfall May, be observed in this lateritic terrain in the humid tropics. It indicates a good potential for further groundwater development. Moreover, conditions are conducive to a considerable contribution to possible recharge to deeper aquifers. the observed groundwater recharge is the result of a complex process on which further research will throw more light.  相似文献   

11.
This work attempted to locate clean and safe groundwater for irrigation use in the Choushui River alluvial fan. Multiple‐variable indicator kriging (MVIK) was adopted to evaluate numerous hydrochemical parameters for a standard of water quality for irrigation in Taiwan. Many hydrochemical parameters in groundwater were distinguished into three main categories—salinity/sodium hazard, nitrogen hazard and heavy metal hazard. Safe and potential hazardous regions of groundwater for irrigation were delineated according to different probabilities estimated by MVIK. The probabilistic results of the classifications gave an opportunity to explore the spatial uncertainty of the hazards and helped government administrators establish a sound policy associated with the development and management of groundwater resources. Analysis of the results indicate that the central distal‐fan and mid‐fan aquifers are the best places to extract clean and safe groundwater for irrigation, and the deep aquifer (exceeding 200 m depth) has wider regions with clean and safe groundwater for irrigation than shallow aquifers. The northern and southern aquifers, with multiple hazards, limit groundwater use for irrigation. Although the proximal‐fan aquifer is a zone of groundwater recharge, the high nitrogen content seriously affects the environment and is not suitable for irrigation use. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

12.
Base flows are important for tropical regions with pronounced dry seasons, which are facing increasing water demands. Base flow generation, however, is one of the most challenging hydrological processes to characterize in the tropics. In many years during the May–December wet season in the Panama Canal Watershed (PCW), base flows in rivers abruptly increase. This increase persists until the start of the December–April dry season. Understanding this unusual base flow jump (BFJ) behaviour is critical to improve water provisioning in the seasonal tropics, especially during droughts and extended dry seasons. This study developed an integrated approach combining piecewise regression on cumulative average base flow and sensitivity analysis to calculate the timing and magnitude of BFJ. Rainfall, forest cover, mean land surface slope, catchment area, and estimated subsurface storage were tested as predictors for the occurrence and magnitude of the BFJs in seven subcatchments of the PCW. Sensitivity analysis on correlated predictors allowed ranking of predictor contributions due to isolated and cross-correlation effects. Correlations between observed BFJs and BFJs predicted by watershed and rainfall-related predictors were 0.92 and 0.65 for BFJ timing and magnitude, respectively. Forest cover was the second most significant predictor after cumulative rainfall for jump magnitude, owing to larger subsurface storage and groundwater recharge in forests than pastures. Catchments in the mountainous eastern PCW always generated larger jumps due to their higher rainfall and greater forest cover than the western PCW catchments. The cross-correlations between predictors contributed to more than 50% of the jump variances. The results demonstrate the importance of rainfall gradient and catchment characteristics in affecting the sudden and sustained BFJs, which can help inform land management decisions intended to enhance water supplies in the tropics. This study underscores the need for more research to further understand the hydrological processes involved in the BFJ phenomenon, including better BFJ models and field characterizations, to help improve tropical ecosystem services under a changing environment.  相似文献   

13.
Over the past century, groundwater levels in California's San Joaquin Valley have dropped by more than 30 m in some areas mostly due to excessive groundwater extraction used to irrigate agricultural lands and sustain a growing population. Between 2012 and 2015, California experienced the worst drought in its recorded history, depleting surface water supplies and further exacerbating groundwater depletion in the region. Due to a lack of groundwater regulation, exact quantities of extracted groundwater in California are unknown and hard to quantify. Recent adoption of the Sustainable Groundwater Management Act has intensified efforts to identify sustainable groundwater use. However, understanding sustainable use in a highly productive agricultural system with an extremely complex surface water allocation system, variable groundwater use, and spatially extensive and diverse irrigation practices is no easy task. Using an integrated hydrologic model coupled with a land surface model, we evaluated how water management activities, specifically a suite of irrigation and groundwater pumping scenarios, impact surface water–groundwater fluxes and storage components and how those activities and the relationships between them change during drought. Results showed that groundwater pumping volume had the most significant impact on long-term water storage changes. A comparison with total water storage anomaly (TWSA) estimates from NASA's Gravity Recover and Climate Experiment (GRACE) provided some insight regarding which combinations of pumping and irrigation matched the GRACE TWSA estimates, lending credibility to these scenarios. In addition, the majority of long-term water storage changes during the recent drought occurred in groundwater storage in the deeper subsurface.  相似文献   

14.
Hydrologic models of irrigated lands generally adopt either a basin-scale or a root-zone perspective. While basin-wide macro-scale models rely on the aggregation of important spatial and temporal data across large areas, micro-scale root-zone models depend on the definition of rigid boundaries around the zone of plant–soil–water interaction. In reality, irrigation management decisions are made on a field by field basis and can interact across field boundaries. This paper first describes a shallow water table model, based on deforming finite element (DFE) framework, to characterize the near-surface field-to-field hydrologic response to various irrigation and drainage management regimes along a gently sloping alluvial fan. The model is then enhanced through changing geometry of a fluctuating water table below a series of irrigated fields. Such an enhancement also offers computational flexibility relative to the saturated–unsaturated models commonly used in micro-scale studies. The model is designed with the alluvial fan aquifers of California’s western San Joaquin Valley as reference systems.  相似文献   

15.
Arsenic in groundwater is a serious problem in New England, particularly for domestic well owners drawing water from bedrock aquifers. The overlying glacial aquifer generally has waters with low arsenic concentrations but is less used because of frequent loss of well water during dry periods and the vulnerability to surface‐sourced bacterial contamination. An alternative, novel design for shallow wells in glacial aquifers is intended to draw water primarily from unconsolidated glacial deposits, while being resistant to drought conditions and surface contamination. Its use could greatly reduce exposure to arsenic through drinking water for domestic use. Hypothetical numerical models were used to investigate the potential hydraulic performance of the new well design in reducing arsenic exposure. The aquifer system was divided into two parts, an upper section representing the glacial sediments and a lower section representing the bedrock. The location of the well, recharge conditions, and hydraulic properties were systematically varied in a series of simulations and the potential for arsenic contamination was quantified by analyzing groundwater flow paths to the well. The greatest risk of arsenic contamination occurred when the hydraulic conductivity of the bedrock aquifer was high, or where there was upward flow from the bedrock aquifer because of the position of the well in the flow system.  相似文献   

16.
The groundwater in shallow loess aquifers in high mountain–hills in the western Loess Plateau in China is almost the sole water resource for local residents. However, the question about how the loess groundwater naturally circulates in these high mountain–hills, characterized by low precipitation and high potential evaporation, remains unclear. The objectives of this study are to evaluate the application of hydrogen and oxygen isotopes to (1) examine temporal variations of the isotopic composition of precipitation and shallow groundwater and (2) uncover the mechanism of groundwater recharge in high mountain–hills. Results from 2 years of monitoring data show a difference in the stable isotopes for groundwater and local precipitation between the winter and summer periods. Similar to precipitation, stable isotopes in groundwater are observed to be depleted in winter and enriched in summer, particularly in oxygen isotope. A prominent characteristic is that H and O isotopes of groundwater show a very clear response to strong precipitation in the rainy season in 2013. The results highlight that local precipitation is the likely recharge source for groundwater in shallow loess aquifers. Annual recharge from local precipitation maintains the groundwater resource in the shallower loess aquifer. The mechanisms governing shallow loess groundwater recharge in high mountain–hills were evaluated. In addition to possible vertical slow percolation of soil water through the unsaturated zone, rapid groundwater recharge mechanisms have been identified as temporal preferential infiltration through sinkholes, slip surface or landslide surface and through the interface of loess layer and palaeo‐soils. Most groundwater can be recharged after a heavy rainy season. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

17.
《水文科学杂志》2013,58(5):949-960
Abstract

A geographical information system (GIS) was used for the integration of hydrological data acquired using remote sensing and geoelectrical techniques to understand the groundwater condition of Bakhar watershed, Mirazpur District, UP, India. Indian remote sensing IRS-1D, LISS—III data were used to prepare a geomorphological and lineament map of the Bakhar watershed. Vertical electrical sounding (VES) was carried out in different geomorphic units, and ranges of electrical resistivity values were assigned to the different formations by calibrating electrical resistivity with borehole data. Based on these, a subsurface resistivity map and an aquifer thickness map were prepared. Several layers were superimposed using GIS techniques. Each theme was assigned a weight, depending on its influence on groundwater recharge. Each class or unit in the map was assigned a knowledge-based rank from one to four, depending on its significance in storage and transmittance of groundwater, and these were then multiplied by the layer weighting to produce a score. Based on these scores, the watershed was categorized into different groundwater potential zones. The results indicate that the eastern and northern parts of the study area have very good groundwater potential to meet the demands of water for irrigation and domestic purposes, whereas the southern region has poor groundwater potential zones. Such integrated analysis has not been attempted so far in this region for hydrogeological investigation.  相似文献   

18.
High‐elevation mountain catchments are often subject to large climatic and topographic gradients. Therefore, high‐density hydrogeochemical observations are needed to understand water sources to streamflow and the temporal and spatial behaviour of flow paths. These sources and flow paths vary seasonally, which dictates short‐term storage and the flux of water in the critical zone (CZ) and affect long‐term CZ evolution. This study utilizes multiyear observations of chemical compositions and water residence times from the Santa Catalina Mountains Critical Zone Observatory, Tucson, Arizona to develop and evaluate competing conceptual models of seasonal streamflow generation. These models were tested using endmember mixing analysis, baseflow recession analysis, and tritium model “ages” of various catchment water sources. A conceptual model involving four endmembers (precipitation, soil water, shallow, and deep groundwater) provided the best match to observations. On average, precipitation contributes 39–69% (55 ± 16%), soil water contributes 25–56% (41 ± 16%), shallow groundwater contributes 1–5% (3 ± 2%), and deep groundwater contributes ~0–3% (1 ± 1%) towards annual streamflow. The mixing space comprised two principal planes formed by (a) precipitation‐soil water‐deep groundwater (dry and summer monsoon season samples) and (b) precipitation‐soil water‐shallow groundwater (winter season samples). Groundwater contribution was most important during the wet winter season. During periods of high dynamic groundwater storage and increased hydrologic connectivity (i.e., spring snowmelt), stream water was more geochemically heterogeneous, that is, geochemical heterogeneity of stream water is storage‐dependent. Endmember mixing analysis and 3H model age results indicate that only 1.4 ± 0.3% of the long‐term annual precipitation becomes deep CZ groundwater flux that influences long‐term deep CZ development through both intercatchment and intracatchment deep groundwater flows.  相似文献   

19.
The hydrology of Quebec, Canada, boreal fens is poorly documented. Many peatlands are located in watersheds with impounded rivers. In such cases, their presence influences reservoir inflows. In recent years, some fens have been subjected to an increase of their wet area, a sign that they may be evolving towards an aquatic ecosystem. This dynamic process is called aqualysis. This article presents the seasonal and monthly hydrological budgets of a small watershed including a highly aqualysed fen (James Bay region). The monitoring of precipitation (P), runoff (Q) and groundwater levels (WL) was conducted during the ice‐free season. Three semiempirical equations (Thornthwaite, Priestley–Taylor and Penman–Monteith) were used and compared to calculate potential evapotranspiration. The first two equations, having fewer parameters, estimate higher potential evapotranspiration values than the third equation. The use of pressure‐level gauges installed in wells, for the calculation of peatland water storage, is inconclusive. Swelling of peat, peat decomposition and plant composition could be responsible for nonnegligible amounts of absorbed water, which are not entirely accounted for by well levels. The estimation of peat matrix water storage is potentially the largest source of error and the limiting factor to calculate water balances in this environment. The results show that the groundwater level and the water storage vary depending on the season and especially after a heavy rainfall. Finally, the results illustrate the complexity of water routing through the site and thus raise several questions to be resolved in the future. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

20.
Water availability is the primary constraint on the improvement of food security in rural areas in northwestern Cambodia. A 4-year study was carried out in the upper Stung Sreng watershed to assess water resources. Four sub-watersheds with different land cover types, ranging in size from 1.5 to 185 km2, were monitored using dedicated weather stations and rain- and streamgauges. Geophysics and observation boreholes were used to characterize aquifers. Rainwater is mostly split into evapotranspiration (annual mean of 54% rainfall) and streamflow components (49%), because groundwater recharge is low (1%). Thus, rainwater and streamflow are the main sources for irrigation development. Groundwater can be used only in specific locations for low water-demand crops. A total of 186 household ponds and three village-scale dams were built and 31 wells were installed. The household pond was determined to be the best solution for irrigation development because of its simple management.
EDITOR A. Castellarin ASSOCIATE EDITOR M. Piniewski  相似文献   

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