Describes the use of a distributed hydrologic model to evaluate different data scenarios. The study attempted to answer questions such as; what will happen to the basin water resources if a) there is a change in climate; b) it is decided that more water must be retained in the river for environmental reasons; c) more water is extracted for urban and industrial use; d) the timing and accounts used for water are changed?
This study was conducted to estimate the impacts of future climate change on the availability of water resources in the Gediz Basin during the 21st century. The Gediz Basin is a watershed along the Aegean coast of Turkey, with a typical Mediterranean climate, in which the most important economic activity is agriculture. Over the last few decades, this basin has been experiencing water-related problems such as water scarcity and competing use of water. In this study, a regional atmospheric model, WRF (the Weather Research and Forecasting Model), and a physically based hydrologic model, WEHY (Watershed Environmental Hydrology Model), were coupled within a hydro-climate modeling framework in order to assess the hydrology and water resources of the Gediz Basin under future climate change. Outputs of four Coupled Model Intercomparison Project Phase 5 (CMIP5) Global Climate Models (GCM), namely, CCSM4, GFDL-ESM2M, HadGEM2-ES, and MIROC5, under two IPCC (The Intergovernmental Panel on Climate Change) representative concentration pathway scenarios (RCP4.5 and RCP8.5) were dynamically-downscaled to 6 km grid resolution by means of the WRF model. These downscaled results were then used as future scenarios for the analysis of the hydrologic response of streamflow to climate change in the basin. In this study, the future projection results of the 21st century (2017 – 2100) were compared to that of the historical period (1985 – 2012). Based on the ensemble average of 8 realizations, the results indicated that the average annual temperatures are expected to increase by 1°C through the 21st century with a statistically significant increasing trend when tested by the non-parametric Mann-Kendall test at 95% confidence level. Moreover, the annual average reservoir inflow volumes are expected to increase by 15.4% when compared to the historical period, but the time series have a statistically significant downward trend throughout the century. The dynamic water balance model developed for this study focused on the major dam of the Gediz Basin, the Demirkopru Dam, which provides water to 88% of its extensive irrigation system. The study focused on this Dam's water supply and water demand in relation to agriculture. The water balance model simulation results showed that the expected cumulative unmet irrigation water demands vary between 570 million m3 (the ensemble average case) and 4740 million m3 (CCSM4 – RCP8.5) during the 21st century. The cumulative unmet irrigation water demands are the greatest in volume during the late part of the 21st century (2073 – 2100). The most optimistic emission scenario under which all the irrigation water demands could be met is GFDL-ESM2M RCP4.5. Even though more water reaches to the reservoir through the 21st century under all GCM realizations, the number of water shortages and drought events increases because of increasing rates of evaporation from the reservoir’s surface, and increasing annual irrigation water demands required by the crops. The results of drought analyses suggest that most of the droughts will last for one month in a three-month irrigation season with a possible intensity of 81 – 120 MCM/month. Moreover, most of the droughts are expected to occur once in every 1 – 3 irrigation seasons. According to the Streamflow Drought Index (SDI) results, the ensemble average case will experience mild droughts during most of the 21st century. In order to mitigate future droughts, this study also examined the effect of the cropping system on the water balances by shifting the cotton growing areas in the current irrigation system, which are the main consumers of the water, to low-water-demand crops that do not need to be watered. The results showed that irrigation water demands can be met under all of the emission scenarios during the 21st century when no water allocation is done for the cotton cultivation in the basin.
A clear understanding of the current water balance is required to explore options for water saving measures. However, measurement of all the terms in the water balance is infeasible in terms of spatial and temporal scale, but hydrological simulation models can fill the gap between measured and required data. For a basin in Western Turkey, simulation modeling at three different scales, field, irrigation scheme and basin scale, was performed to obtain all terms of the water balance. These water balance numbers were used to calculate the Productivity of Water at the three spatial levels distinguished to assess the performance of the systems.
This report investigates how much water is required to maintain the freshwater reed beds that are the main shelter and breeding place for threatened bird species. The ability of Gediz basin to fulfill this requirement and the effects of this requirement on irrigated agriculture, the major competitor for water in the Gediz basin were subsequently examined.
In this report, the concept and procedures of hydronomic (hydro water + nomus management) zones are introduced. A set of six hydronomic zones are developed and defined based on key differences between reaches or areas of river basins. These are the: Water Source Zone, Natural Recapture Zone, Regulated Recapture Zone, Stagnation Zone, Final Use Zone, and Environmentally Sensitive Zone. The zones are defined based on similar hydrological, geological and topographical conditions and the fate of water outflow from the zone. In addition, two conditions are defined which influence how water is managed: whether or not there is appreciable salinity or pollution loading; and whether or not groundwater that can be used for utilization or storage is present. Generic strategies for irrigation for four water management areas, the Natural Recapture, Regulated Recapture, Final Use, and Stagnation Zones, are presented. The Water Source Zone and Environmentally Sensitive Zone are discussed in terms of their overall significance in basin water use and management.
Natural resources conservation is one of the dilemmas currently facing mankind in both developed and the developing world. The topic is of particular importance for the latter, where the majority depend on terrestrial ecosystems for livelihood; more than one billion people live in abject poverty earning less than a dollar per day; more than 3.7 billion suffer from micronutrient deficiency and more than 800 million suffer from chronic hunger. Population increase, resource use conflicts, technological advancements, climate change, political doldrums, and unsustainable use and harvesting of resources have all put more pressure on natural resources leading to land degradation and poverty. To achieve a win-win situation, we need to change our mindset by thinking outside the box through advocating integrated and holistic approaches in managing our natural resources. This book presents a variety of sustainable strategies and/or approaches including use of GIS and Remote Sensing technologies, decision support system models, involvement of stakeholders in major decisions regarding use of natural resources, community level initiatives, and use of surveillance and monitoring mechanisms.
Deforestation and forest degradation represent a significant fraction of the annual worldwide human-induced emission of greenhouse gases to the atmosphere, the main source of biodiversity losses and the destruction of millions of people's homes. Despite local/regional causes, its consequences are global. This book provides a general view about deforestation dynamics around the world, incorporating analyses of its causes, impacts and actions to prevent it. Its 17 Chapters, organized in three sections, refer to deforestation impacts on climate, soil, biodiversity and human population, but also describe several initiatives to prevent it. A special emphasis is given to different remote-sensing and mapping techniques that could be used as a source for decision-makers and society to promote forest conservation and control deforestation.
This book provides an in-depth description of water resources of Turkey, a country with a unique geographical location, extending from the Mediterranean in Europe to the Middle East. Its varying geography, topography, hydrology, geology and climate are reflected in the diverse characteristics of its water basins. Furthermore, due to its geographical location, Turkey has a significant number of transboundary river basins and has to share its water resources with its neighbors, an issue that can sometimes lead to water conflicts. Turkey is also an interesting example of a developing country that is attempting to adapt to universal water management strategies while at the same time facing legal, institutional, economic and capacity development problems. It has long remained a water-rich country, but the situation is now changing due to the increasing population, inefficient use of resources, and the impacts of climate change and environmental degradation. This book is useful for national and international organizations as well as water resources professionals. It takes on an added significance in the light of climate change in the region, water management problems and transboundary water basins.
