Water Resource Management for Ecosystem Health: Theory, Methods and Applications

Water yield as an important ecosystem service for mitigating water scarcity in drylands, is quite sensitive to land use and climate change. Evaluating the response of water yield to land use policies in drylands under climate change is conducive to sustainable water resource management. Taking the Hohhot-Baotou-Ordous-Yulin region in the northwest of China as an example, this study used the methods of the InVEST model, trend analysis, comparative experiment, PLUS model to explore the spatial-temporal trends and driving factors of water yield variation, as well as to simulate the future water yield under different land use policy scenarios. The results showed that (1) water yield in the study area fluctuated and increased from 14.14 mm to 46.59 mm during 2000 to 2020, the places with a significant increasing trend of water yield were mainly distributed in the southeast loess hilly area; (2) climate change is the major driving factor of water yield variation with a contribution rate of 85.8–99.6%, but land use change played an increasingly important role in affecting water yield; (3) the Grain-Security-Dominated (GSD) land use policy scenario would generate the highest water yield in 2030 under climate conditions of SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5, while the Regional-Greening-Dominated (RGD) land use policy scenario has the lowest water yield in the future. The results could provide reference for the decision-making process of ecological restoration and land use planning in drylands. Full article

Land suitability assessment for irrigation is critical to inform as well as manage current and future irrigated agriculture production systems. Land suitability analysis determines whether a given land area could potentially be used for specific crop production. The objective of this study was to identify the availability of suitable land for surface irrigation systems for the production of millet, sorghum, sugarcane, and wheat production in the Lower Omo Gibe plain, Southern Ethiopia. Land suitability analysis was performed by a parametric method using factors such as soil texture, effective soil depth, Calcium Carbonate (CaCO₃), soil electrical conductivity (ECe), drainage class, and slope. Five land suitability classes were identified that include highly suitable (S1), moderately suitable (S2), marginally suitable (S3), currently not suitable (N1), and permanently not suitable (N2). Results showed that 6.6, 7.5, 6.6, and 6.6% of the study area mostly located in the western part of the basin, were highly suitable (S1) for irrigated millets, sorghum, sugarcane, and wheat crops production, respectively. However, the mountainous areas in the central part of the basin were classified as N2 due to the steep slope and shallow soil depth. Overall, the results of the study revealed that the use of various suitability analysis techniques could assist in identifying suitable land for irrigated agriculture. Full article

The pressure on freshwater resources is leading to diminishing flows in some of the critical river systems across the globe. India is no exception, and this is mainly because of water withdrawal for irrigation, which is often to the tune of 70% to 80% of the lean season flows, with some proportion for domestic and industrial use. While graduating from the concept of environmental flows and its assessment methodologies in India, the water-managers, the researchers and the conservationists are now moving towards answering the next question, if the rivers are to be revived, where will the water come from, especially in the case of over-allocated rivers, including the River Ganga. While the logical way is to look at the biggest user of water, i.e., irrigation, it remains to be seen whether the irrigation water savings will actually lead to enhancing flows in a river, complementing the efforts towards maintaining e-flows in rivers, or whether it will lead to more area under agriculture, bring changes in cropping patterns towards more water-intensive crops or result in something else. This is a growing debate across the globe, where India is no exception, and there has been a wide range of opinions in this regard. This paper discusses the process, findings and lessons from a joint initiative involving farmers, the Uttar Pradesh state Irrigation and Water Resources Department, Bijnor District Administration and a conservation organisation, WWF, to enhance flows in a sub-tributary, called the Karula River, which is part of the Ganga River system. Another objective of this paper is to look at the scalability and replicability of similar approaches in other irrigation command areas to benefit nearby river systems in general. Under this initiative, the team attempted to enhance flows in the river Karula by routing the saved water from irrigation supplies in a canal commanded area. This saving of water is being achieved due to supply-side and demand-side measures that are being adopted in the project area. With the objective of ensuring the sustainability of the initiative, efforts are made to form an institutional arrangement, through which this initiative can be sustained beyond the project support. Full article