Lake Tengiz. Photo credit: NASA
The ADB is committed under its Water Operational Plan 2011-2020 to undertake expanded and enhanced analytical work to enable its developing member countries to secure deeper and sharper understanding of water issues and solutions. IHE Delft, in partnership with IWMI, therefore implemented various studies under the assignment “Expanding support to Water Accounting in River Basins and Water Productivity Measurements in Irrigated projects” (42384-012). The studies aim to support (a) ADB’s lending and non-lending assistance in the water sector, and (b) the design of irrigation projects at an early stage at selected candidate projects.
IHE Delft and IWMI created comprehensive, comprehensible and accessible information on available water resources and their current uses in major river basins. The focus for the irrigation projects is on providing baseline data for parameters related to land and water productivity and identifying suitable interventions (i.e. through water productivity analyses). The main focus is on making the best use of remote sensing data and information to inform decision making.
The analyses contributed to various ADB funded projects in six countries (Cambodia, India, Kazakhstan, Mongolia, Philippines and Sri Lanka). The focus of the analyses was on using remote sensing information to assess the water resources situation at basin level (Water Accounting – WA+) and to assess the spatial (and temporal) variability of land and water productivity in irrigation schemes (Water Productivity - WP). The methodology applied is detailed in the methodology report.
The water accounting study in Cambodia supports the Irrigated Agriculture Improvement Project (CAM 51159-002). It focuses on one of the irrigation schemes listed in the project, the Kamping Pouy irrigation scheme, located in one of the tributaries of the Tonle Sap river basin. In addition to assessing the water availability for the scheme, the study provides an inter-basin comparison between the different tributaries of Tonle Sap. A Relative Water Deficit parameter (RWD) was produced as a proxy to inform where problems may exist with water delivery across the command areas.
The study was implemented in close collaboration with the Advanced Center for Integrated W ater Resources Management (ACIWRM) to support the Karnataka Integrated and Sustainable Water Resources Management Investment Program - Tranche 2 (IND 43253-026). The Krishna basin is the fifth largest river basin in India shared between four states: Karnataka (44%), Maharashtra (26.7%), Telangana (20%), and Andra Pradesh (9.3%). Water accounts were developed to analyse the water resources conditions of three sub-basins of Krishna located in Karnataka state: Middle Krishna (K2), Ghatprabha (K3), and Malprabha (K4).
The Water Accounting study in Mongolia focussed on the Selenge river basin and one of the su b-basins (Sugnugur) where ADB intends to support the rehabilitation of an irrigation system. The analyses contributed to the Vegetable production and irrigated agriculture project (MON 51423-002) and the Implementing Innovative Approaches for Improved Water Governance project (MON 51099-001). In addition, a field-scale WP study was done for the 2 center pivots of the Plant Science and Agricultural Training and Research Institute, one of the beneficiaries of the study.
The Philippines case study is supporting the Mindanao Irrigation Development Project (PHP 53272-001). The water accounting study for the Philippines therefore focuses on the Minda nao Island, which is the second-largest island of the island nation of the Philippines, covering a total area of 97,530 km2. It is endowed with abundant water resources, annual average rainfall of between 1,800-3,000 mm/year. The tropical monsoon climate combined with the rugged volcanic topography of the island results in considerable variability in water supply across geographic regions and over time. Next to the inter-basin comparison of the eight largest river basins, additional analyses were performed on 8 irrigation schemes located on the island, with particular focus on the dry season
The water accounting study for Kazakhstan supports the Irrigation rehabilitation project (KAZ 50387-001) and focusses on the Nura-Sarysu river basin. The Nura-Sarysu WEB is an internal drainage basin, entirely located within the country borders of Kazakhstan covering an area of 139,700 km2. As the majority of the agriculture takes place with in the Nura river basin, which drains to Lake Tengiz, the focus of the water accounting analyses was on the drainage catchment of Lake Tengiz
The WP analyses in Tamil Nadu supported the Climate Adaptation in Vennar Subbasin in Cauvery Delta Project (CAVSCDP; Loan-3394-IND). It focuses on the Vennar command areas (also referred to in the CAVSCDP as the “Vennar subbasin”), which covers an area of 4,154 km2. A Relative Water Deficit parameter (RWD) was produced as a proxy to inform where problems may exist with water delivery across the command areas.
The WP study in Sri Lanka supports the Integrated Water Productivity Improvement Project (SRI 52156-001) (IWPIP). The remote sensing analysis was conducted for 25 basins located in North Western, Uva, and Southern Provinces; four priority river basins have been selected: (i) Deduru Oya and Mi Oya in the North Western Province, and (ii) Kirindi Oya and Menik Ganga which straddle the Uva and Southern Province. The study focuses on an assessment of crop phenology, as well as for the 4 priority basins, focusing on a water productivity assessment
The WP study was implemented in close collaboration with the Advanced Center for Integrated Water Resources Management (ACIWRM) to support the Karnataka Integrated and Sustainable Water Resources Management Investment Program - Tranche 2 (IND 43253-026). The WP studies are carried out in the Narayanpur Left Bank Canal (NLBC) command area under Upper Krishna Project (UKP) in Northern Karnataka state in India. This study focuses on the NLBC network which comprises an irrigated area of 451,703 ha. The NLBC is divided into six culturable command areas (CCAs) that are supported by the branch canals
The WP analyses conducted in Cambodia are intended to support the Irrigated Agriculture Improvement Project; this Project will assist the Government of Cambodia to modernize and improve the climate and disaster resilience of four irrigation systems in Battambang, Kampong Cham, Kampong Thom, and Takeo provinces to supply water to 43,500 hectares. The area selected for the water productivity study is the Kamping Pouy Irrigation System (KPIS) in Battambang Province. The KPIS system serves 19,000 ha, from which 12,000 ha is the command area of the subproject. The activity focused on the generation of actual evapotranspiration from remote sensing data for the scheme, the analysis of water deficits calculated from this, and the estimation of above ground biomass production across the irrigation scheme.
The activities undertaken for Kazakhstan focused in the Karaghandy region, and were intended to support the proposed Irrigation Rehabilitation Sector Project which is being prepared as part of Kazakhstan Government’s “State Program on Development of Agricultural Industry for 2017-2021”. In the Karaghandy region the Project will finance rehabilitation of 6 canals and 23 pipelines in 10 schemes of 6 districts, namely Abai, Zhezkazgan, Zhanaarka, Bukhar-Zhyrau, Osakarovka and Nura districts.
Through this project, IHE Delft Institute for Water Education and the International Water Management Institute (IWMI) are partnering to deliver spatially disaggregated data and trends in water availability, consumption and productivity in key selected ADB project areas. FAO is responsible for further integration and publication of the data in AQUAMAPS, the global spatial database on water and agriculture that complements AQUASTAT statistical data.
As part of the project, two webinars were organized in collaboration with ADB, one on water productivity and one on water accounting.
During the webinar, IHE Delft and IWMI shared the outcomes of their water productivity measurement work. They introduced the concept and methodology of remote sensing-based water productivity, showcasing the results of three water productivity studies and examples of how water productivity results can impact decision-making
The webinar introduced the concept of water accounting and the Water Accounting Plus (WA+) methodology, and provided examples on how water accounting can be used in decision-making, noting different ADB case studies part of the two phases of water accounting work done since 2017. Lastly, a vision for the future of remote sensing-based water accounting was presented.