WaterSubject

For many fishery management purposes, it is often necessary to estimate the number of fish present in linear water bodies such as rivers, canals and drainage channels. A variety of methods are available to do this, but all require significant physical effort from a team of people and thus impose large costs on the organisation responsible. Cost and practical limitations often mean that variability and error are difficult to estimate for a particular sampling programme, reducing the scientific credibility and the practical ... Read More

Anthropogenic acidification seriously hit Swedish lakes and watercourses from the early 1960s and onwards following the increased emissions of sulphur oxides in Europe. A national remediation programme through large-scale liming of inland waters was launched in 1976. Although the acid deposition now continuously declines, an improved liming programme is still in action treating ca. 6000 lakes. The aim is to detoxify the water by restoring pH and alkalinity thereby making it available for acid-sensitive or Al-sensitive biota. Effects and experiences of acidification ... Read More

The ecological process in the Tarim River, Xinjiang, northwest China, has undergone great changes due to human disturbance over the past 50 years. Most notably, alteration in the spatial-temporal pattern of water resources has resulted in a damaged or degraded vegetative ecosystem in the lower reaches of Tarim River, a condition that restricts local economical development. However, after raising the water level by watering to the lower Tarim River, such ecological degradation was obviously reversed within a certain region of the water ... Read More

Stormwater runoff from urbanized watersheds has been receiving increasing attention from the public and scientific community in recent years because it is perceived to be a large source of pollutants to coastal waterbodies around the nation. Despite separate stormwater and sanitary sewer systems in southern California, the stormwater runoff from urbanized watersheds has contributed substantial loadings of a variety of constituents to receiving water environments. For example, the cumulative loads of lead and zinc from all of the urbanized watersheds in the ... Read More

Irrigation performance and water productivity can be benchmarked if estimates of spatially distributed yield and crop water use are available. A commonly used method to estimate crop evapotranspiration in irrigated areas is to multiply reference evapotranspiration values by appropriate crop coefficients. This study evaluated convenient ways to derive such coefficients using multispectral vegetation indices obtained by remote sensing. Detailed ground radiometric measurements were taken in small plots perpendicular to the crop rows to obtain canopy reflectance values. Ancillary measurements of green ground ... Read More

Irrigation delivers major benefits in food security and human development. Irrigation also leads to waterlogging and salinity which threaten the sustainability of irrigated agriculture and pose major socioeconomic and environmental risks. The issue can be addressed by limiting net recharge to groundwater such that the water and salt keep natural equilibria. Often the information on net recharge within catchments is unavailable, particularly at lower spatial scales such as the farm or paddock; this offers little guidance for on-farm land and water management ... Read More

Field experiments were conducted for 2 years to investigate the effects of various levels of nitrogen (N) and methods of cotton planting on yield, agronomic efficiency of N (AEN) and water use efficiency (WUE) in cotton irrigated through surface drip irrigation at Bathinda situated in semi-arid region of northwest India. Three levels of N (100, 75 and 50% of recommended N, 75 kg ha?1) were tested under drip irrigation in comparison to 75 kg of N ha?1 in check-basin. The three methods ... Read More

The combined use of remote sensing and a distributed hydrological model have demonstrated the improved understanding of the entire water balance in an area where data are scarcely available. Water use and crop water productivity were assessed in the Upper Bhima catchment in southern India using an innovative integration of remotely sensed evapotranspiration and a process-based hydrological model. The remote sensing based Surface Energy Balance Algorithm for Land (SEBAL) was used to derive an 8 month time series of observed actual evapotranspiration ... Read More

Irrigated agriculture in Pakistan is mainly confined to the Indus plains where it has been developed by harnessing the principal water resources available to the country. The contiguous Indus basin irrigates an area of about 16 million ha. Under the Indus water treaty of 1960 the total water available to Pakistan from the Indus River system was 181 × 109 m3, approximately 75% of the annual available flow. Of the available water, about 131 × 109 m3 is diverted to the 43 ... Read More

After 1990, external loads of Central European rivers with inorganic nutrients (nitrogen and phosphorus) and organic material were reduced because of changed environmental laws. However, in the eutrophic lowland River Warnow, North-Eastern Germany, nitrate concentrations remained high with 35–185 ?mol l?1 without a significant decrease since 1992. In contrast, phosphate concentrations, varying between 0.3 and 5.2 ?mol l?1 during the growth season 2002, decreased significantly over the years. However, its concentrations still exceeded 1 ?mol l?1 regularly in the growth seasons. This ... Read More