This paper presents an overview of the current water resources scenario in India, and recent work carried out in India to assess the climate change impact on hydrology and water resources. Issues that need to be addressed with respect to climate change/variability in sustainable water resources planning and management are discussed. 相似文献
Groundwater systems in arid regions will be particularly sensitive to climate change owing to the strong dependence of rates of evapotranspiration on temperature, and shifts in the precipitation regimes. Irrigation use in these arid regions is typically a large component of the water budget, and may increase due to changes in soil moisture resulting from higher temperatures and changes in the timing of precipitation events. In this study, future predicted climate change scenarios from three global climate models (CGCM1 GHG+A1, CGCM3.1 A2, and HadCM3 A2) are used to determine the sensitivity of recharge to different climate models in an irrigated agricultural region. The arid Oliver region (annual precipitation 300 mm) in the Okanagan Basin, British Columbia, is used to demonstrate the approach. Irrigation return flow, as a contribution to total diffuse recharge, is simulated by calculating the daily applied irrigation based on estimates of seasonal crop water demand and the forecasted precipitation and evaporation data. The relative contribution of irrigation return flow to groundwater recharge under current and future climate conditions is modelled. Temperature data were downscaled using Statistical Downscaling Model (SDSM), while precipitation and solar radiation changes were estimated directly from the GCM data. Shifts in climate, from present to future predicted, were applied to a stochastic weather generator, and used to force a one-dimensional hydrologic model, HELP 3.80D. Results were applied spatially, according to different soil profiles, slope and vegetation, over a 22.5 km by 8.6 km region. Changes to recharge in future time periods for each GCM result in modest increases of recharge with the peak recharge shifting from March to February. Lower recharge rates and higher potential evapotranspiration rates are similarly predicted by all three models for the summer months. All scenarios show that the potential growing season will expand between 3 and 4 weeks due to increases in temperature. However, the magnitude of the change varies considerably between models. CGCM3.1 has the largest increases of recharge rates, CGCM1 has very minor increases, and HadCM3 is relatively stable (as indicated by the near-zero changes between climate states). The significant differences between these three models indicate that prediction of future recharge is highly dependent on the model selected. The minor increase of annual recharge in future predicted climate states is due the shift of peak recharge from increased temperature. Irrigation rates dominate total recharge during the summer months in this arid area. Recharge in irrigated areas is significantly higher than natural recharge, with irrigation return flow between 25% and 58%. A comparison of recharge results for the least efficient and the most efficient irrigation systems indicates that the latter are more sensitive to choice of GCM. 相似文献
The impact assessment of molasses‐based distillery‐effluent irrigation on groundwater quality around village Gajraula in the district of Jyotiba Phule Nagar, Uttar Pradesh, India was studied by sampling groundwater on monthly intervals consecutively for summer, winter and monsoon seasons during 2006–2007 and water quality parameters, viz. pH, electrical conductivity (EC), chloride (Cl?), sulphate (SO), nitrate (NO), chemical oxygen demand (COD), total solids (TS), total dissolved solids (TDS), sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), zinc (Zn2+), iron (Fe3+), and total coliforms (TC) were monitored. Results depicted that the values of all parameters decreased with increasing depth of water table. Sulphate, nitrate and potassium contents were maximal in agricultural site during monsoon while EC, Cl?, TS, TDS, Na+, Ca2+, Mg2+, Zn, and Fe were maximal in industrial sites during summer. Groundwater samples of residential site harboured maximum coliforms especially during monsoon, highlighting threat to groundwater. Significant positive correlation matrix between coliforms with nitrate, sulphate and potassium ions explained their survival on these nutrients. To overcome this, important measures emphasizing improvement in effluent treatment technology matching site‐specific characteristics are recommended for eco‐friendly ferti‐irrigation. 相似文献
This study was directed toward a preliminary assessment of nitrate degradation in northeast Iowa soils. Soil experimental plots were created with variable combinations of fertilizers, ethanol, irrigation, and plant growth. The maximum average concentration of nitrate was much higher in the chemically fertilized plots (500 mg/km) than those fertilized organically (120 mg/kg). This was attributed to the excessive ammonia volatilization from the applied cow manure. Soil nitrate dropped from 155 to 50 mg/kg in a matter of 3 weeks in the deep samples of the intermittently irrigated plots. This is because higher soil moisture lowered the oxygen level, which favored denitrification. Although ethanol seemed to have restricted the release of nitrate in the manure-treated plots, the data are not conclusive. The highest degradation of soil-nitrate (lowest recovered 38 mg/kg) was observed in the plots that simultaneously grew corn, received cow manure, and were not irrigated. Soils in these plots were depleted of nitrogen by ammonia volatilization from manure, and through the uptake by corn plants. Nitrification of organic nitrogen to nitrate was restricted in plots that were left without irrigation. Rain events helped nitrification on the surface, but promoted denitrification at depth. 相似文献
In India, the quantity and quality of water available for irrigation is variable from place to place. Assessment of water
quality has been carried out to determine the sources of dissolved ions in groundwater. Quality of groundwater in a 398 km2 Peddavanka watershed of a semi-arid region of south India is evaluated for its suitability for drinking and irrigation purposes.
The middle Proterozoic Cuddapah Supergroup and Kurnool Group of rocks underlie most of the watershed. The main lithologic
units consist chiefly of quartzite, limestone, and shale. Seventy-six water samples were collected from open-wells and bore-holes.
Water samples were collected representative of the post-monsoon (winter) and pre-monsoon (summer). The quality assessment
is made through the estimation of Ca2+, Mg2+, Na+, K+, Cl−, SO42−, CO32−, HCO3−, total hardness as CaCO3, TDS, EC, and pH. Based on these analyses, parameters like sodium adsorption ratio, % sodium, residual sodium carbonate,
non-carbonate hardness, potential salinity, Kelley’s ratio, magnesium ratio, index of base exchange and permeability index
were calculated. According to Gibbs‘ ratio samples in both seasons fall in the rock dominance field. The overall quality of
waters in the study area in post-monsoon season is high for all constituents ruling out pollution from extraneous sources. 相似文献
The simulations of dynamic, spatially distributed non-linear models are impacted by the degree of spatial and temporal aggregation of their input parameters and variables. This paper deals with the impact of these aggregations on the assessment of irrigation scheme performance by simulating water use and crop yield. The analysis was carried out on a 7000 ha irrigation scheme located in Southern Spain. Four irrigation seasons differing in rainfall patterns were simulated (from 1996/1997 to 1999/2000) with the actual soil parameters and with hypothetical soil parameters representing wider ranges of soil variability. Three spatial aggregation levels were considered: (I) individual parcels (about 800), (II) command areas (83) and (III) the whole irrigation scheme. Equally, five temporal aggregation levels were defined: daily, weekly, monthly, quarterly and annually.
The results showed little impact of spatial aggregation in the predictions of irrigation requirements and of crop yield for the scheme. The impact of aggregation was greater in rainy years, for deep-rooted crops (sunflower) and in scenarios with heterogeneous soils. The highest impact on irrigation requirement estimations was in the scenario of most heterogeneous soil and in 1999/2000, a year with frequent rainfall during the irrigation season: difference of 7% between aggregation levels I and III was found. Equally, it was found that temporal aggregation had only significant impact on irrigation requirements predictions for time steps longer than 4 months. In general, simulated annual irrigation requirements decreased as the time step increased. The impact was greater in rainy years (specially with abundant and concentrated rain events) and in crops which cycles coincide in part with the rainy season (garlic, winter cereals and olive).
It is concluded that in this case, average, representative values for the main inputs of the model (crop, soil properties and sowing dates) can generate results within 1% of those obtained by providing spatially specific values for about 800 parcels. 相似文献
Differences in the impact of irrigation with freshwater versus wastewater on the underlying shallow groundwater quality were investigated in the Coastal Aquifer of Israel. Seven research boreholes were drilled to the top-most 3–5 m of the saturated zone (the water table region-WTR) in the agricultural fields. The unsaturated zone and the WTR below the irrigated fields consist mainly of clayey sands, while the main aquifer comprises mainly of calcareous sandstones and sands. We show that the salinity and composition of the groundwater at the WTR are highly variable over a distance of less than 1 km and are controlled by the irrigating water and the processes in the overlying unsaturated zone. Tritium data in this groundwater (4.6 tritium units (TU)) support that these water are modern recharge. The water at the WTR is more saline and has a different chemical composition relative to the overlying irrigation water. High SAR values (sodium adsorption ratio) in wastewater irrigation lead to absorption of Na+ onto the clay and release of Ca2+ into the recharging water, resulting in low Na/Cl (0.4 compared to 1.2 in the wastewater) and high Ca/Cl ratios. In contrast, in the freshwater-irrigated field the irrigation water pumped from the aquifer (Na/Cl=0.9; SAR=0.6) is modified into Na-rich groundwater (Na/Cl=2.0) due to reverse base-exchange reactions. The high NO3 concentration (>100 mg/l) in the WTR below both fields is derived from the agricultural activities. In the freshwater field, the source of NO3 is fertilizer leachates, whereas in the wastewater field, where less fertilizers are applied, nitrate is probably derived from nitrification of the NH4 in the wastewater. Some of the original inorganic nitrogen in the wastewater is consumed by the agricultural plants, resulting in a lower inorganic-N/Cl ratio in the WTR as compared to that in the wastewater. This study demonstrates the important role of the composition of irrigation water, combined with lithology and land use, in determining the quality of the water that recharge the aquifer below agricultural fields. 相似文献
Due to uneven spatial and temporal distribution of rainfall and lack of sufficient water management technologies, the development
activities of the society are totally depending on groundwater resources. In addition to the prevailing drought-prone conditions,
the improperly treated and unplanned release of effluents of industry, municipal and domestic into the nearby streams and
ponds and the majority usage of groundwater for irrigation are increasing the ionic concentration of the groundwater and making
it more saline. The analytical results of the collected groundwater samples show that the groundwater is alkaline, and sodium
and bicarbonate are the dominant cation and anion, respectively. Gibbs variation diagram shows that the control of the chemistry
of groundwater in the study area is the weathering of granitic gneisses and also the leaching of evaporated and crystallized
ions from the topsoil of the irrigated areas and improperly treated industrial effluent ponds. GIS, a potential tool for facilitating
the generation and use of thematic information, has been applied and analyzed for identification of groundwater quality suitable
zones for domestic and irrigation purposes. 30.06% of the area is with suitable, 67.45% of the area is with moderately suitable
and 2.45% of the area is with unsuitable quality of groundwater for domestic purpose. 46% of the area is with suitable, 53.36%
of the area is with moderately suitable and 0.64% of the area is with unsuitable quality of groundwater for irrigation purpose. 相似文献