Influences of Soil Physical Properties on Water-Supplying Capacity

The water-supplying capacity of two agricultural soils, red soil in Jiangxi Province and meadow soil in Henan Province, was assessed mainly using physical investigations. The reticulated mottting horizon in the red soil was a horizon limiting roots distribution due to its high density and hardness in structure and low pH (pH 5.05). The resistance of the red soil to drought hazard was poor because of its low water-supply capacity and poor hydraulic conductivity. The meadow soil had superior profile infiltration to that of the red soil and great available water-storage capacity) which resulted in low run-off loss, especially in the wheat-growth season. It was difficult for water stored in the deep layers of the meadow soil to reach the surface due to the low unsaturated hydraulic conductivity of its clay-rich horizon in subsoil. However, water stored in deep layers was still available because the roots could extend to the deep layers due to the relatively low density in soil structure.

Eutrophication development and its key regulating factors in a water-supply reservoir in North China

Yanghe Reservoir is an important source of drinking water for Qinhuangdao City,North China;however,in recent decades this water source has been eutrophic with recurrent summer cyanobacterial blooms.The trophic grade of the system in summer was mesotrophiceutrophic in 1990 and became hypertrophic in 2011.The nutrient availability is extremely high during the entire year,and the water temperature should be the primary driver of the summer blooms.In May-October of 2010 and 2011,abrupt variations were observed in the Secchi depth（SD） and chlorophyll a（Chl-a）,and both the correlated analysis of Chl-a-SD and trophic status indices（TSI） deviation（TSI Chl-a-TSI SD） showed that algal cell density dominated light attenuation.During the algal bloom outbreak,the microcystin concentration was found to vary between 0.35-2.12 μg/L in 2010 and 0.11-1.86 μg/L in 2011.The maximum microcystin content was more than two times the safety limit required for drinking water.Inflow discharges were most concentrated in the summer,with periods of lower residence time and the largest water level fluctuation over the entire year.When a high availability of nutrients promoted a high Chl-a concentration in the whole system,it appeared that the instability caused by the decrease in residence time could not produce effective changes in the cyanobacterial abundance.The results indicated that nutrient enrichment in the aquatic systems of Yanghe Reservoir is the most serious problem and that the status would not been modified effectively by increasing hydrological fluctuations（e.g.,decreasing the residence time）.Therefore,decreasing the nutrient concentrations is the only route to improve the water quality of this reservoir.

Estimation of Natural-Technogeneous Pollution of Underground Waters in Horezm Region of Uzbekistan

Nowadays,the resources of underground water present itself as a valuable mineral and are to be the most important and in many regions one and only source of economic-drinking water-supply.For the past years,in connection with fast development of industry and agriculture,there occurred the tendency of increasing necessity in usage of underground water resources for production-technical needs,irrigation of

Multi-reservoir joint operating rule in inter-basin water transfer-supply project

The joint operation of inter-basin water transfer-supply(IBWTS)project can be more complex when there is joint water demand in multi-reservoir system and multi-importing reservoirs simultaneously transferring water from exporting reservoir.In this study,a joint operating rule is proposed for the purpose of solving such complex operation problem.This rule is composed of a set of sub-rules,including hedging rule curves of virtual aggregation reservoir(i.e.equivalent reservoir)and other individual reservoirs,water-transfer rule curves of each individual reservoir,as well as some of important assisted rules.These assisted rules refer to allocation models for water transfer-supply.In the proposed rule,an equivalent reservoir is established to determine under what condition the water supply should be reduced and specify the total supplied water for joint water demand(i.e.aggregation method).Allocation models are developed to distribute the total transferred water into each importing reservoir and determine the water releases for joint water demand by each member reservoir of the aggregation system(i.e.decomposition method).And these models are integrated with a set of influence factors such as hydrologic characteristics,reservoir storage or vacant storage,regulating ability,water-supply pressure,and so on.The aggregation of multi-reservoirs and the disaggregation of water quantities are taken into a whole consideration to reduce the complexity in reallocation of water target storage or water release.Finally,the proposed rule is applied to the North-line IBWTS Project in Liaoning Province,China.The results indicate that the proposed rule can take full advantage of hydrologic compensation in basins and capacity compensation in reservoirs.Thus it can improve the utilization efficiency of water resources in system.