An Analysis of Economic Growth and Industrial Wastewater Pollution Relations in China

This paper investigates the relationship between the income growth and the trend in industrial wastewater discharge in China during the period 1981-2007. For the data encompassing all the provinces over the entire period considered, both an inverted U-shaped EKC and an N-shaped EKC are statistically significant. An analysis dividing provinces into rich and poor groups reveals that the EKC relations are mainly governed by the rich province group. The EKC relations for the poor province group are either not found or are statistically weak. A further analysis based on dividing the data into before and after the year 2000 is in favour of the quadratic EKC model. The results of this study show that the relationships between a given pollutant and income are temporal and spatial specific depending on the driving forces behind. This implies that results derived from one study for certain regions/countries and for a specific time period may not be generalized for other regions/countries and extrapolated to other periods

Conditioning DRASTIC model to simulate nitrate pollution case study: Hamadan-Bahar plain

One of the major causes of groundwater pollution in Hamadan-Bahar aquifer in western Iran is a non-point source pollution resulting from agricultural activities. Withdrawal of over 88% of drinking water from groundwater resources, adds urgency to the studies leading to a better management of water supplies in this region. In this study, the DRASTIC model was used to construct groundwater vulnerability maps based on the "intrinsic” (natural conditions) and "specific” (including management) concepts. As DRASTIC has drawbacks to simulate specific contaminants, we conditioned the rates on measured nitrate data and optimized the weights of the specific model to obtain a nitrate vulnerability map for the region. The performance of the conditioned DRASTIC model improved significantly (R 2=0.52) over the intrinsic (R 2=0.12) and specific (R 2=0.19) models in predicting the groundwater nitrate concentration. Our study suggests that a locally conditioned DRASTIC model is an effective tool for predicting the region's vulnerability to nitrate pollution. In addition, comparison of groundwater tables between two periods 30years apart indicated a drawdown of around 50m in the central plain of the Hamadan-Bahar region. Our interpretation of the vulnerability maps for the two periods showed a polluted zone developing in the central valley requiring careful evaluation and monitorin

Factors Affecting Farmers Decisions on Fertilizer Use: A Case Study for the Chaobai Watershed in Northern China

The Chaobai watershed in northern China is the most important source of drinking water for Beijing. The level of fertilizer use, especially overuse, as well as farming practices in the region have therefore a great impact on the water quality downstream. This study analyses the factors influencing farmers’ decision on fertilizer use and the implications for water quality. The analysis is based on a survey of 349 farm households. It takes into consideration both farm and farmer specific characteristics and farmers’ subjective evaluation of factors shaping their decisions. Regression models are used to examine the determinants of fertilizer use intensity across farm households and to investigate the factors influencing the overuse of nitrogen. The results suggest the significance of many of these ‘subjective’ factors, indicating the importance of considering them in the analyses. The results also show that irrigation, gains in crop yield and farming goal of earning are positively correlated to fertilizer use intensity while farm size, manure application, soil fertility and the distance to fertilizer market are negatively correlated. Investigation of the overuse problem shows that higher education level significantly reduces the probability of overfertilization. Based on these findings a few policy relevant implications are discussed

Streamflow Modeling in a Highly Managed Mountainous Glacier Watershed Using SWAT: The Upper Rhone River Watershed Case in Switzerland

Streamflow simulation is often challenging in mountainous watersheds because of irregular topography and complex hydrological processes. Rates of change in precipitation and temperature with respect to elevation often limit the ability to reproduce stream runoff by hydrological models. Anthropogenic influence, such as water transfers in high altitude hydropower reservoirs increases the difficulty in modeling since the natural flow regime is altered by long term storage of water in the reservoirs. The Soil and Water Assessment Tool (SWAT) was used for simulating streamflow in the upper Rhone watershed located in the south western part of Switzerland. The catchment area covers 5220km2, where most of the land cover is dominated by forest and 14% is glacier. Streamflow calibration was done at daily time steps for the period of 2001-2005, and validated for 2006-2010. Two different approaches were used for simulating snow and glacier melt process, namely the temperature index approach with and without elevation bands. The hydropower network was implemented based on the intake points that form part of the inter-reservoir network. Subbasins were grouped into two major categories with glaciers and without glaciers for simulating snow and glacier melt processes. Model performance was evaluated both visually and statistically where a good relation between observed and simulated discharge was found. Our study suggests that a proper configuration of the network leads to better model performance despite the complexity that arises for water transaction. Implementing elevation bands generates better results than without elevation bands. Results show that considering all the complexity arising from natural variability and anthropogenic influences, SWAT performs well in simulating runoff in the upper Rhone watershed. Findings from this study can be applicable for high elevation snow and glacier dominated catchments with similar hydro-physiographic constraint

Water regime of metal-contaminated soil under juvenile forest vegetation

In a three-year factorial lysimeter study in Open Top Chambers (OTCs), we investigated the effect of topsoil pollution by the heavy metals Zn, Cu, and Cd on the water regime of newly established forest ecosystems. Furthermore, we studied the influence of two types of uncontaminated subsoils (acidic vs. calcareous) and two types of irrigation water acidity (ambient rainfall chemistry vs. acidified chemistry) on the response of the vegetation. Each of the eight treatment combinations was replicated four times. The contamination (2700mgkg−1 Zn, 385mgkg−1 Cu and 10mg kg−1 Cd) was applied by mixing filter dust from a non-ferrous metal smelter into the upper 15cm of the soil profile, consisting of silty loam (pH6.5). The same vegetation was established in all 32 lysimeters. The model forest ecosystem consisted of seedlings of Norway spruce (Picea abies), willow (Salix viminalis), poplar (Populus tremula) and birch (Betula pendula) trees and a variety of herbaceous understorey plants. Systematic and significant effects showed up in the second and third growing season after canopies had closed. Evapotranspiration was reduced in metal contaminated treatments, independent of the subsoil type and acidity of the irrigation water. This effect corresponded to an even stronger reduction in root growth in the metal treatments. In the first two growing seasons, evapotranspiration was higher on the calcareous than on the acidic subsoil. In the third year the difference disappeared. Acidification of the irrigation water had no significant effect on water consumption, although a tendency to enhance evapotranspiration became increasingly manifest in the second and third year. Soil water potentials indicated that the increasing water consumption over the years was fed primarily by intensified extraction of water from the topsoil in the lysimeters with acidic subsoil, whereas also lower depths became strongly exploited in the lysimeters with calcareous subsoil. These patterns agreed well with the vertical profiles of fine root density related with the two types of subsoil. Leaf transpiration measurements and biomass samples showed that different plant species in part responded quite differently and occasionally even in opposite ways to the metal treatments and subsoil conditions. They suggest that the year-to-year changes in treatment effects on water consumption and extraction patterns were related to differences in growth dynamics, as well as to shifts in competitiveness of the various species. Results showed that the uncontaminated subsoil offered a possibility to compensate the reduction in root water extraction in the topsoil under drought, as well as metal stres

KINEROS2 application for land use/cover change impact analysis at the Hulu Langat Basin, Malaysia

The impacts of land use/cover changes (LUCC) on a developed basin in Malaysia were evaluated. Three storm events in different intensities and durations were required for KINEROS2 (K2) calibration and LUCC impact analysis. K2 validation was performed using three other rainfall events. Calibration results showed excellent and very good fittings for runoff and sediment simulations based on the aggregated measure. Validation results demonstrated that the K2 is reliable for runoff modelling, while K2 application for sediment simulation was only valid for the period 1984-1997. LUCC impacts analysis revealed that direct runoff and sediment discharge increased with the progress of urban development and unmanaged agricultural activities. These observations were supported by the NDVI, landscape and hydrological trend analyses

Modeling Crop Water Productivity Using a Coupled SWAT–MODSIM Model

This study examines the water productivity of irrigated wheat and maize yields in Karkheh River Basin (KRB) in the semi-arid region of Iran using a coupled modeling approach consisting of the hydrological model (SWAT) and the river basin water allocation model (MODSIM). Dynamic irrigation requirements instead of constant time series of demand were considered. As the cereal production of KRB plays a major role in supplying the food market of Iran, it is necessary to understand the crop yield-water relations for irrigated wheat and maize in the lower part of KRB (LKRB) where most of the irrigated agricultural plains are located. Irrigated wheat and maize yields (Y) and consumptive water use (AET) were modeled with uncertainty analysis at a subbasin level for 1990–2010. Simulated Y and AET were used to calculate crop water productivity (CWP). The coupled SWAT–MODSIM approach improved the accuracy of SWAT outputs by considering the water allocation derived from MODSIM. The results indicated that the highest CWP across this region was 1.31 kg·m−3 and 1.13 kg·m−3 for wheat and maize, respectively; and the lowest was less than 0.62 kg·m−3 and 0.58 kg·m−3. A close linear relationship was found for CWP and yield. The results showed a continuing increase for AET over the years while CWP peaks and then declines. This is evidence of the existence of a plateau in CWP as AET continues to increase and evidence of the fact that higher AET does not necessarily result in a higher yield

SWAT-based hydrological modelling of tropical land-use scenarios

The Hulu Langat basin, a strategic watershed in Malaysia, has in recent decades been exposed to extensive changes in land-use and consequently hydrological conditions. In this work, the impact of Land Use and Cover Change (LUCC) on hydrological conditions (water discharge and sediment load) of the basin were investigated using the Soil and Water Assessment Tool (SWAT). Four land-use scenarios were defined for land-use change impact analysis, i.e. past, present (baseline), future and water conservation planning. The land-use maps, dated 1984, 1990, 1997 and 2002, were defined as the past scenarios for LUCC impact analysis. The present scenario was defined based on the 2006 land-use map. The 2020 land-use map was simulated using a cellular automata-Markov model and defined as the future scenario. Water conservation scenarios were produced based on guidelines published by Malaysia’s Department of Town and Country Planning and Department of Environment. Model calibration and uncertainty analysis was performed using the Sequential Uncertainty Fitting (SUFI-2) algorithm. The model robustness for water discharge simulation for the period 1997–2008 was good. However, due to uncertainties, mainly resulting from intense urban development in the basin, its robustness for sediment load simulation was only acceptable for the calibration period 1997–2004. The optimized model was run using different land-use maps over the periods 1997–2008 and 1997–2004 for water discharge and sediment load estimation, respectively. In comparison to the baseline scenario, SWAT simulation using the past and conservative scenarios showed significant reduction in monthly direct runoff and monthly sediment load, while SWAT simulation based on the future scenario showed significant increase in monthly direct runoff, monthly sediment load and groundwater recharge

Hydrologic responsiveness of a Lower Fraser Valley lowland soil

Soil degradation in the lowland soils of the Lower Fraser Valley area is an off-season (September-April) problem. The legacy of the degradation process is encountered every year in the form of ponding which delays farming operations such as cultivation and seeding. It is common for the lowland soils in west Delta to be left in a bare, loose, and therefore unstable state in the fall after harvest. As the result of raindrop impact on such a soil, a disaggregation process takes place which decreases the saturated hydraulic conductivity, the saturated water content, the air entry pressure head, and the water releasing ability of a soil. As a result of these changes the hydrologic responsiveness of a soil will decrease, decreasing its ability to allow rapid infiltration and drainage. The objective of this thesis was firstly, to investigate the causes of the soil structural degradation and secondly, to use some of the soil structural parameters to optimize the responsiveness of a soil and thirdly, to suggest a management model with the objective of improving the hydrologic responsiveness of a lowland soil. To fulfill the above objectives, in the first chapter, the process of soil degradation was studied on large undisturbed soil columns removed from two adjacent locations within an area of Ladner in west Delta, British Columbia. It was found that a disaggregation process caused by the impact of raindrops on a weakly aggregated soil was the main cause of a low hydrologic responsiveness at the beginning of the cultivation season. As a result of degradation of the soil surface layer, a surface seal can form with a saturated hydraulic conductivity in the order of 9.7x10⁻¹⁰ m s⁻¹. A surface seal can effectively decrease the infiltration rate, leading to the formation of a persistent pond which will make a soil untrafficable and unworkable. In the second chapter, a concept of "designer soil" was developed, where a set of "design hydrologic parameters" were identified for a partially hypothetical soil. A soil possessing hydrologic parameters better than the design parameters would therefore display a certain desired hydrologic responsiveness. In the third chapter, a descriptive management model was suggested with the objective of achieving the design parameters as identified in the second chapter.Land and Food Systems, Faculty ofGraduat