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Ankara Üniversitesi (2002)

Drought management plan for Ankara

CEYLAN Abdullah

Titre : Drought management plan for Ankara

Ankara’nın kuraklık yönetim planı

Auteur : CEYLAN Abdullah

Université de soutenance : Ankara Üniversitesi

Grade : Master of Science (MSc) 2002

A drought is a period of drier-than-normal conditions that results in water- related problem. Precipitation ( rain or snow ) falls in uneven patterns across the county. The amount of rain and snow also varies with the seasons. In some areas, most of the yearly precipitation falls during the late summer and fall. Even the total amount of rainfall for a year is about average, rainfall shortage can occur during a period when moisture is critically needed for plant growth. When no rain or only a very small amount of rain falls, soil can dry out and plants can die. When rainfall is less than normal for several weeks, months or years, the flow of streams and rivers declines, water level in lakes and reservoirs fall, and the depth to water in wells increases. If dry weather persists and water-supply problems develop, the dry the dry period can become a drought. The beginning of a drought is difficult to determine. Several weeks, months, or even years may pass before people know that a drought is occurring. The end of a drought can occur as gradually as it began. Dry period can last for 10 years or more. The first evidence of drought usually is seen in records of rainfall. Within a short period of time, the amount of moisture in soils can begin to decrease. The effects of a drought on flow in streams and rivers or on water levels in lakes and reservoirs may not be noticed for several weeks or months. Water levels in wells may not reflect a shortage of rainfall for a year or more after a drought begins. A period of below-normal rainfall does not necessarily result in drought conditions. Some rain returns to the air as water vapor when water evaporates from 124water surfaces and from moist soil. Plant roots draw some of the moisture from the soil and return it to the air through a process called transpiration. The total amount of water returned to the air by these processes is called evapotranspiration. Sunlight, humidity, temperature and wind affect the rate of evapotranspiration. When evapotranspiration rates are large, soils can lose moisture and dry conditions can develop. During cool, cloudy weather, evapotranspiration rates may be small enough to offset periods of below normal precipitation and a drought may be less severe or may not develop at all. Some areas are more likely to have drought than other areas. In humid, or wet regions, a drought of a few weeks is quickly reflected in a decrease in soil moisture and in declining flow in streams. People who use water from streams in these areas may face water shortages as soon as streamflow begins to decline. In arid, or dry regions, people rely on ground water and water in reservoirs to supply their needs. They are protected from short-term droughts, but may have severe problems during long dry periods because they may have no other water source if wells or reservoirs go dry. When droughts occur, there is not enough water to supply all needs. If water is diverted from streams in irrigate crops, streamflow will decrease. Reservoirs that may already be at low levels will be drawn even lower to supply water for power generations, to supply water to downstream cities and towns, or to maintain river levels high enough for navigation. Decreasing water levels in rivers, lakes, and reservoirs may cause problems for fish and wildlife that depend on wetlands or water bodies to survive. 125Balancing the needs of all the users of a water supply during a drought can be very difficult. Local or State agencies must take decisions on how water will be used to satisfy the most critical needs and to reduce economic and environmental problems. In times of severe drought, water users must cooperate and share the limited mount of water available to protect the critical needs of people, fish and wildlife, agriculture, and industry. Conserving water is very important during drought periods. Water saved by one user may be enough to protect the critical needs of others. Irrigation practices can be changed to use less water or crops that use less water can be planted. Cities and towns can ration water, factories can change manufacturing methods, and individuals can practice water-saving measures to reduce consumption. Last drought conditions occurred in Ankara obviously showed that it is essential to prepare an effective drought management plan immediately. Most of the studies proved that the population of Ankara is growing rapidly but conversely the water resources are limited and not enough to demand. In this study, a sample drought management plan is prepared according to the net water in the reservoirs and to demand of people.


Page publiée le 27 janvier 2023