Assessment of Runoff and Sediment Yields Using the AnnAGNPS Model in a Three-Gorge Watershed of China

Soil erosion has been recognized as one of the major threats to our environment and water quality worldwide, especially in China. To mitigate nonpoint source water quality problems caused by soil erosion, best management practices (BMPs) and/or conservation programs have been adopted. Watershed models, such as the Annualized Agricultural Non-Point Source Pollutant Loading model (AnnAGNPS), have been developed to aid in the evaluation of watershed response to watershed management practices. The model has been applied worldwide and proven to be a very effective tool in identifying the critical areas which had serious erosion, and in aiding in decision-making processes for adopting BMPs and/or conservation programs so that cost/benefit can be maximized and non-point source pollution control can be achieved in the most efficient way. The main goal of this study was to assess the characteristics of soil erosion, sediment and sediment delivery of a watershed so that effective conservation measures can be implemented. To achieve the overall objective of this study, all necessary data for the 4,184 km2 Daning River watershed in the Three-Gorge region of the Yangtze River of China were assembled. The model was calibrated using observed monthly runoff from 1998 to 1999 (Nash-Sutcliffe coefficient of efficiency of 0.94 and R2 of 0.94) and validated using the observed monthly runoff from 2003 to 2005 (Nash-Sutcliffe coefficient of efficiency of 0.93 and R2 of 0.93). Additionally, the model was validated using annual average sediment of 2000–2002 (relative error of −0.34) and 2003–2004 (relative error of 0.18) at Wuxi station. Post validation simulation showed that approximately 48% of the watershed was under the soil loss tolerance released by the Ministry of Water Resources of China (500 t·km−2·y−1). However, 8% of the watershed had soil erosion of exceeding 5,000 t·km−2·y−1. Sloping areas and low coverage areas are the main source of soil loss in the watershed

The environmental impact assessment for Bastora dam

Barajlar nehir akışlarını düzenlemek ve kuru dönemlerde yeterli su teminini sağlamak için binlerce yıldır kullanılmaktadır. Gelecekte, nüfus artışı ve su tüketimi arttıkça, birçok kişi daha fazla baraja ihtiyaç olacağını düşünüyor. Bastora barajının ÇED çalışmasının ana hedefleri, baraj projesinin Ekolojiye ve halkın sosyo-ekonomik/sağlık durumuna potansiyel etkilerini belirlemek/değerlendirmektir. Çalışma, barajların çevresel etkilerini değerlendirmek için bol miktarda alan ve veri toplamadan oluşmaktadır. Bu çalışma, Bastora Deresinin tepe akışının bir bölümünü 200milyon.m 3 'lük bir akış depolama rezervuarı haline getirmiştir. Depolanan suyun temel amacı, ekinleri ve meyve ağaçlarını yetiştirmek için aşağı yukarı toplam arazinin 11,000 hektarından 4.000 hektarını sulamak olacaktır. Proje alanında, yeraltı suyu özellikle kırsal alanda tarım, çevre, sağlık, ev ve gelişme için önemli bir girdidir. Yeni bir araştırmaya göre, su ihtiyacının yaklaşık 60%'ı kentsel ve banliyö alanları boyunca dağılmış çok sayıda derin kuyu tarafından karşılanırken, Bu ihtiyacın 40%‟ı Büyük Zap Nehri'nden , Ifraz istasyonundan Erbil yakınlarındaki arıtma tesisine pompalanarak tedarik edilmektedir. FAO 2004'e göre, kuyu derinlikleri sadece yakın zamanda artmış ve en çok yeni kuyu 100 metreyi aşan bir derinliğe kadar inilmiştir. Şu anda Erbil ilçesinde 1.000'den fazla operasyonel derin kuyu bulunmayabilir. Kullanılabilir yeraltı suyu miktarının 2,5m3 /sn'yi aşmadığı sonucuna varılabilir. Proje alanının nüfusu yaklaşık 60.000 kişi olup, nüfus yoğunluğu km2 başına 450 kişidir. Yıllık ortalama yağış 260 mm ila 515 mm arasinda değişmektedir. Yaz aylarında ortalama yıllık sıcaklık 35oC'yi aşar ve kış aylarında 9 oC ile 15oC arasında değişir. Sonuç olarak, olumlu etkiler olumsuz etkilerden önemli ölçüde daha yüksektir ve bu barajın bu alanın gelişmekte olan bir parçası olduğu düşünülmektedir. Böylece, bu baraj üzerinde yeniden işlenmesi şiddetle tavsiye edilir

Dams and Sustainable Development Goals: A Vital Interplay for Sustainability

The dawn of civilization has seen more advancements in numbers and technology of dam across the globe than any other. The reservoir has been a decent source of water for domestic, industrial, recreational and agricultural usage. The failure of any dam structure has diverse ramifications on the natural environment and biodiversity. This work studied the role of dam in the realization of the sustainability agenda of the United Nations. The seventeen (17) Sustainable Development Goals (SDGs) are linked to the proper functioning of dams as a source of municipal and rural water supply. Effect of climate change on dam, its failures and operational impact on agriculture and biotic and abiotic ecosystem were also considered. It was noted that the interaction between this water source and SDGs are direct and indirect, positive and negative. The conclusion drawn was that water structure such as dams has main roles to play in sustainability and many of the SDGs can be achieved by functional water system at all levels. Developing good maintenance culture is essential. Keywords: Biodiversity, Climate Change, Dam, GHG, Reservoir, Sustainability, SDGs, Wate

The Analysis of Large Dam Impacts on Sediment Grain Size Distribution in a Tropical River System

Sedimentation is a natural phenomenon of rivers that is enhanced by modification of the river basin. The presence of dams delays the exchange of sediments, nutrients, and organisms between the terrestrial and aquatic environments. This article assesses the impact of the Selangor dam on the sediment grain size distribution and its association with river velocity and discharge. The fieldwork for sampling is conducted in the normal and rainy seasons. The samples were analyzed through a sieve analysis procedure to determine the particle size of the sediments. After the sieve analysis technique, GRADISTAT analysis was performed on the output. The GRADISTAT analysis classifies the sediments between sandy gravel and sand, and the median grain size (D50) ranges from 4.00 to 0.18 mm. The spatial distribution of the D50 shows that the bed-load sediments of the upper Selangor River are becoming fine-grained downstream. The skewness of the sediments differs from 0.86 to 8.44, which indicates that the sediments are poorly to moderately well sorted. The Spearman's correlation of the D50 and river velocity and discharge determine no association of the D50 with river velocity and discharge. The stations near Selangor Dam have high slopes and receive "sediment hungry" water that washes small-sized sediments; therefore, the upper stations have a more significant amount of gravel and large sand. Doi: 10.28991/CEJ-SP2023-09-02 Full Text: PD

Mentzelia chrysantha Engelmann ex Brandegee (golden blazing star): a technical conservation assessment

Prepared for: the USDA Forest Service, Rocky Mountain Region, Species Conservation Project.July 3, 2006

Proceedings of 2021 Kentucky Water Resources Annual Symposium

This symposium was planned and conducted as a part of the state water resources research institute annual program that is supported by Grant/Cooperative Agreement Number G20AS00025 from the United States Geological Survey (USGS). The contents of this proceedings document and the views and conclusions presented at the symposium are solely the responsibility of the individual authors and presenters and do not represent the official views of the USGS or of the symposium organizers and sponsors. This publication is produced with the understanding that the United States Government is authorized to reproduce and distribute reprints for government purposes. Mention of trade names or commercial products does not constitute their endorsement by the USGS

Improved water and land management in the Ethiopian highlands: its impact on downstream stakeholders dependent on the Blue Nile; Intermediate Results Dissemination Workshop February 5-6, 2009, Addis Ababa, Ethiopia

River basin management, Watershed management, Farming systems, Water balance, Reservoirs, Water supply, Irrigation requirements, Irrigation programs, Simulation models, Sedimentation, Rainfall-Runoff relationships, Erosion, Soil water, Water balance, Soil conservation, Institutions, Organizations, Policy, Water governance, International waters, Institutional and Behavioral Economics, Land Economics/Use, Resource /Energy Economics and Policy,

Environmental Challenges and Impacts of Land-Use Conversion in the Yellow River Basin

While the Chinese population continues to grow, Chinese policy makers are faced with a seemingly insurmountable task of satisfying demands for fresh water, electricity, agricultural products, etc. Not only is the irrigated land area presently shrinking, as previously cultivated is converted to various non-agricultural purposes, but additionally, advancing pollution from expanding mining industries, urban centers, and upstream input-intensive farmlands, are causing a reduction in the usability of the Yellow River water. Unfavorable climatic, topographic, and geomorphic preconditions further constrain food production potentials. The exceptionally high silt load and sedimentation rate in the Yellow River constitute another major challenge for engineers. Dam construction and maintenance work are aggravated by rapid sedimentation in reservoirs, undermining potentials for water supply storage and electricity production. Likewise, flood prevention measures in the Lower Reaches are counteracted by sediment build-up in the canal. In the entire basin, freshwater constitutes an advancing challenge, with regard to its usability, storage, allocation, and absolute seasonal availability. Based on a review of potential river ecological impacts of irrigation and multi-purpose dams, this report concludes that advancing intensification of agricultural practices and continuous construction of large dams may significantly alter riverine ecosystems with adverse implications for human livelihoods. The author argues that any larger intervention in the riverine landscape should by necessity be preceded by a comprehensive assessment of the river's various functions and values for its different user groups. Such an assessment should consider not only the physical, but also the water quality and biological aspects and their interrelations. Just as many scientists tend to focus only on a few research parameters, managerial strategies often tend to target only one or a few objectives at a time. Balancing the different interests at hand, based on a comprehensive but understandable environmental impact assessment, is identified as the key to successful integrated river basin management

Colorado water, May/June 2012

The newsletter is devoted to enhancing communication between Colorado water users and managers and faculty at the state's research universities.Newsletter of the Water Center of Colorado State University. Theme: Student research