Influencing Factors Analysis of Taiwan Eutrophicated Reservoirs

Abstract

Treatment cost and quality of domestic water are highly correlated with raw water quality in reservoirs. This study aims to identify the key factors that influence the trophic state levels and correlations among Carlson trophic state index (CTSI) levels, water quality parameters and weather factors in four major reservoirs in Taiwan from 2000 to 2017. Weather (e.g., air temperature, relative humidity, total precipitation, sunlight percentage and cloud cover) and water quality parameters (e.g., pH, chemical oxygen demand, suspended solids (SS), ammonia, total hardness, nitrate, nitrite and water temperature) were included in the principal component analysis and absolute principal component score models to evaluate the main governing factors of the trophic state levels (e.g., CTSI). SS were washed out by precipitation, thereby influencing the reservoir transparency tremendously and contributing over 50% to the CTSI level in eutrophicated reservoirs (e.g., the Shihmen and Chengchinghu Reservoirs). CTSI levels in the mesotrophic reservoir (e.g., Liyutan Reservoir) had strong correlation with chlorophyll-a and total phosphorus. Results show that rainfall/weather factors were the key driving factors that affected the CTSI levels in Taiwan eutrophicated reservoirs, indicating the need to consider basin management and the impacts of extreme precipitation in reservoir management and future policymaking.

Water Quality Assessment of a Hydro-Agricultural Reservoir in a Mediterranean Region (Case Study—Lage Reservoir in Southern Portugal)

“…Several studies reported that values of low transparency can be caused by the presence of high amounts of particles and solutes [40][41][42][43], which in the present study can be supported by the positive Spearman correlation with EC and Mg (EC: R = 0.537, p < 0.05; Mg: R = 0.491, p < 0.05; see Table S3). These results agreed with a study carried out in 50 surface waters in Greece, with the results showing that the lakes most impacted by agricultural and urban activities (highest salt content) had the lowest transparency values [44].…”

Using Multiple Indices for the Water Resource Management of a Monomictic Man-Made Dam in Southern Africa

“…where CTSI is the The limitation of the cTSI as reported by the literature is that this model tends to overestimate the trophic levels, partly due to its consideration of the highest productive seasons such as spring and summer in temperate lakes. Consequently, researchers and different studies have adopted different approaches to assess the trophic status of lakes in tropical and subtropical regions and dams that are sensitive to data variability [7].…”

“…However, water in the dam may still be used for irrigation purposes. Putri et al [7] indicated that Africa has adopted the WQI as a monitoring program because it is a strong and reliable index composed of physical, chemical, and biological variables for the determination of water quality. However, this current study contradicts the background provided by Putri et al [7], as there is no known country in Africa that is using the WQI as part of their management practices, except for researchers exploring this option for consideration by decision-makers.…”

“…This is a major concern to water quality authorities as the outcome affects water quality and increases treatment costs, which have direct implications for the economy. Treatment costs and the quality of domestic water are highly correlated with raw water in dams [7]. In South Africa, the estimated unit cost for various options (i.e., primary, secondary, and advanced treatment-the removal of suspended solids) of WWTWs is estimated to be R 9,857,094.00/M ($559,594.45/M ) [8].…”

Towards Monitoring of Nutrient Pollution in Coastal Lake Using Remote Sensing and Regression Analysis

“…Anthropogenic activities have a direct and indirect impact on the environment [1]. One such type of water pollution is eutrophication, a case of algal bloom caused by increasing levels of nutrients [2,3]. As part of the water pollution management, it is important to detect and manage pollution sources [4,5].…”