Assessing the Effects of Practiced Irrigation Methods on Irrigation Water Demand and Allocation among Farmers in Kontsa Irrigation Project, Ethiopia

Increasing of demand for water, allocation of limited water resources, climatic variability, degradation of water in the environment and developing of policies for sustainable water use are issues of increasing concern in the Kontsa irrigation project. This study aimed at assessing the effects of selected irrigation methods on water demand and allocation among farmers in Kontsa irrigation project. The study employed both primary and secondary data. The primary data were collected by interviewing 80 farmers, key informant interviews and observation of the project area while secondary data were collected from different agencies of Ethiopia. For this study Water Evaluation and Planning (WEAP) model was used to model the current situation of irrigation water demand and also to create scenario for future irrigation water demand. The model was set up for a current account year in 2015 and last year of scenarios in 2040 based on the available data. Then the irrigation water demand of the project area was modeled while giving consideration for existing and planned developments in the area. The result from the current situation of irrigation water demand indicated that the demand was satisfied fully and the unmet demand under the base year (2015) was zero. Additionally, irrigation expansion scenario was created and the result of this scenario indicates the increment of irrigation water demand as compared to the base year and the reference scenario. The study also revealed that furrow irrigation and plastic buckets were the main irrigation techniques employed by farmers in the study area.

Assessing effects of climate change on irrigation water demand in the Lombok River Basin, Indonesia

Irrigation water demand in the command area is affected by rainfall and climate conditions in the river basin. In climate change conditions, rainfall and temperature are predicted to increase and projected to impact irrigation water requirements significantly. Therefore, understanding the climate change effects on irrigation demand in the command area is significant to the river basin manager and planner for managing water resources effectively. This study aims to predict the impact of climate change and irrigation efficiency improvement on the irrigation water requirement in 2032-2040. This study used the CropWat model to estimate irrigation water requirements in 1995-2005 and 2032-2040. Irrigation water demand in the Dodokan watershed as a part of the Lombok river basin was computed using the historical rainfall and climate data from observation stations. Further, the observed data from 2006 to 2014 were projected into climate change in 2032-2040 as an input for the model to predict the demand in corresponding years. Result suggests that the change of annual irrigation water demand in the Dodokan watershed was expected to rise by 1.61% in 2032-2040 compared with 1995-2005, and irrigation efficiency improvement effort would decrease the demand -18.18% in the climate change period.

Water Balance Supporting the Irrigation Water Demand in Java Island, Indonesia

Java is the most populous island with the largest percentage of rice fields in Indonesia. However, rice fields in Java Island often experience water shortages, so an analysis of the potential water availability for irrigation in Java is required. This research aims to analyze water's potential to meet irrigation water needs in each catchment area in Java. In this research, the potential for irrigation water in Java is calculated based on the balance of water balance between water availability and DMI and Irrigation water needs. This research is divided into two parts: (1) analysis of water availability using the WFLOW hydrological simulation; and (2) water demand analysis based on population statistical data. Based on this research, it can be concluded that the water balance between water resources and irrigation water needs in Java is still in the surplus category, even though there are deficits in several catchment areas (WS): in the Kepulauan Seribu, Wiso Gelis, and Welang Rejoso WS. WS with the most water availability is generally located in wide (WS) areas, while several WS with abundant water needs is generally located in WS with the densest population. According to The Central Bureau of Statistics (BPS), the agricultural area in Java has decreased by an average of 20 thousand hectares per year, so that the demand for irrigation water on the island of Java will also decrease. Consequently, the excess water potential in Java Island needs to be allocated to meet the needs of DMI, which are increasing every year. In addition, the results also show that the development of irrigation areas in the future should be focused on large (WS) areas that have the potential for significant amounts of irrigation water.

Desain Pintu Air Berbantu Komputer Untuk Saluran Irigasi Tersier di Daerah Irigasi Cikarawang Bogor

Irrigation water gate was one of the supporting components of agricultural activities, especially the management of rice fields, because it was utilized in the management of water flow. The implementation of water gate has a complex and interdependent set of tasks. So that was the problem which can made undesired effects. So that, the planning can be shorted by computer design . Besides, the changes in a design could be overcome quickly and precisely. The purpose of this research is to the effective rainfall, evapotranspiration, discharge of irrigation water needs in the Cikarawang irrigation area, produce a design of computer-aided water gate, and know RAB for the construction of the water gate. The study was conducted from April to July 2020. The place to do the research was Cikarawang Village, Bogor Regency, West Java. The results of the study were the design of water gate by using data plotting with computer-aided script files (SCR). The effective rainfall of 1806.3 mm, the highest evapotranspiration of 5.5 mm/day and the lowest evapotranspiration of plants at 4 mm/day, the highest irrigation water demand was 2.18 lt/dt/ha, The dimensions of 0.5 x 0.75 x 0.012 m, and water gate opening 0.27 m. These water gate openings were used when the plant's water requirements are highest. The cost of making water gate made from fiberglass is Rp. 838.000,-while for steel costs Rp. 3.500.000,-.

Comparison of FAO Crop Reference Estimates and Radiation based Estimates for Daily Reference Evapotranspiration Estimation

<p>Reference evapotranspiration (ETo), a hypothetical concept to estimate evapotranspiration from irrigated and large grass fields is crucial in finding the irrigation water demand in places with extensive agricultural practice. In general, the FAO method (based on the Penman-Monteith equation) is used to estimate ETo from stations that are placed in locations that violate the requirements for reference evapotranspiration. In this study we compare radiation-based methods used to estimate reference evapotranspiration such as ETo De Bruin and ETo Makkink with more conventional ETo approaches in FAO PM method and Priestley Taylor method using in-situ measurements from stations placed in two different settings: (1) Areas that are well-irrigated but surrounded by dry land, (2) Areas that are dry but extensive. We use two spatially dense networks of stations: 1) CIMIS stations of California located in irrigated and in-extensive fields, (2) MESONET stations of Oklahoma located on dry surfaces.  We analyze the differences in the ETo estimates and hypothesize that the radiation-based estimates give more accurate results in the conditions given above for irrigation advisory. We also assess the spatial variability of the different ETo estimates and attempt to investigate the reason behind the differences in these estimates due to the climatic factors.</p>

Climate change impacts on irrigation water resource in Switzerland

<p>According to climate projections, rainfall rates and summer discharge from snow and glacier melt in Switzerland are expected to decrease by the end of the 21<sup>st</sup> century. This may lead to limited water availability for irrigation in agriculture in the future and high irrigation water demand especially during the summer months, which consequently enhances the problem of water scarcity for agriculture.</p><p>These predicted changes make the identification of timescales, frequencies, and geographical pattern of water scarcity a fundamental concern for future agricultural practices. Therefore, the main aim of this work is to investigate climate change impacts on water resources and the consequences on irrigation water supply in Switzerland. By creating maps of the geographic distribution of natural water resources available according to climate projections until the end of the 21<sup>st</sup> century using ArcGIS, the severity of water scarcity is quantified, while regional differences and the most affected areas can be revealed.</p><p>The expected outcomes are increasing days of water scarcity per year over the course of the 21<sup>st</sup> century, while those regions furthest away from melt water sources and lakes will be most affected. This in turn might lead to restricted irrigation potential, making more efficient water use indispensable in Switzerland, while creating general shifts to more water-resistant crops in Swiss agricultural practices.</p>

ALTERNATIF SKENARIO PEMANFAATAN AIR EMBUNG NELAS BERDASARKAN KARAKTERISTIK KETERSEDIAANNYA

East Nusa Tenggara Province is a province that has many embungs. Embung Nelas, in Lamaknen District, Belu Regencyis planned to meet the water demand of the population and cattle in Makir & Lamaksenulu Village as well as field water demand in Makir Village. Embung Nelas is design by using dependable flow Q 80%. From the calculation, Embung Nelas can meet the water demand in Makir and Lamaksenulu villages until 2040 for a population of 5888 people, 4029 large cattle, 1739 small livestock and 3277 chicken, as well as the irrigation water demand of 23 hectares the Makir Village Considering that the rainy conditions are not the same every year, a water use scenario is made based on the water conditions. There are 4 discharge conditions, dry discharge (Q97.3%), low discharge (Q 80%), normal water discharge (50.7%) and sufficient water discharge (26%). The simulation results in the other 3 scenarios, were obtained for the dry discharge of Embung Nelas in 2040 which was only able to irrigate 76% of raw water and cattle, in normal water conditions it could irrigate 6.6 Ha more fields and in sufficient water it could irrigate 12.9 Ha more fields. Keywords: Embung, Dependable flow, Simulation, Scenario

Reducing sugarcane irrigation demand through planting date adjustment in Alagoas State, Brazil

ABSTRACT Sugarcane is both an important crop for the Brazilian Northeast economy, which faces severe water scarcity, and a water-intensive crop. Thus, it is important to develop irrigation strategies to reduce irrigation water demand in the region. This study aims to determine the sugarcane planting date that results in the maximum rainwater availability to the crop in the growing cycle. The crop effective precipitation was estimated from a soil water balance performed during three planting cycles of sugarcane, cultivar ‘RB 92579’. The crop was planted under subsurface drip irrigation in five months: October, November, December, January, and February, corresponding to the dry season period of the region. The experiment was conducted at the Açúcar e Álcool Coruripe Mill, located in the Coruripe municipality, State of Alagoas, Brazil, during the years 2012 to 2016. For all planting dates and growing cycles studied, the average effective rainy precipitation was equal to 30% of the total rainfall under irrigated conditions and 54.5% without considering the irrigation component in the soil water balance. November was the planting date that resulted in the minimum irrigation depth for the sugarcane growing cycle, with the potential irrigation water saving ranging from 5 to 129 mm.