Assesment of Ecological Flow for Mountain Rivers of the Kura Basin

Abstract

Development of an irrigation farming and intensive water use in water catchments areas of Kura basin river of Azerbaijan has increased consumption to fresh water, which is supplied only by small mountain rivers. Most of water resources of small mountain rivers of Kura basin are completely consumed by the enterprises of industry and agriculture. Waste of the water resources of small rivers bring to the “loss of rivers” as an element of landscape in the Small Caucasus region. In lower part of Kura river basin within the Azerbaijan during the shallow season of year the river flow is completely absent. To prevent such condition on the mountain rivers needs to reserve a part of the river flow, that is to say, reserve “ecological flow” in the riverbeds. Ecological flow is such a quantity and condition of the flow, in which is vital for aquatic organisms, quarantines increase for them, sufficient for transporting all solid materials and sediments. In other words, the ecological flow maintains the river ecosystem as a part of an environment. To quarantine of these conditions are needed enough quantity, quality and strong watercourse speed in the riverbeds. The complex assessment of the ecological flow needs systematical and complex hydrological, biological and ecological investigations and stationary observations on the watersheds. As a result of long-term investigations, new methodic, which gives a possibility to calculate ecological flow for mountain rivers is proposed. For sufficient situation of hydroecological safety, ecological flow is needed to estimate for points of concentration of rivers. Points of concentration in many small rivers are situated very far from the river mouthes and consequently, stationary hydrological observations do not reflect hydroecological situations in the mountain rivers. By the offered methodic it is possible to estimate ecological flow for all year period. By this methodic the ecological runoff is estimated not only for water gauge stations, but also for a mouthes of small rivers. The index of a relativity of a ecological flow is developed. It has been revealed, that the interrelation between recordable and ecological flows defines an ecological situation in river ecosystem. Such interrelation may be called relative hydroecological factor of flow (CREF). Relative ecological factor of the water is an indicator of ecological situation in the river for any period. If the CREF value is higher than the unit is, then the danger of ecological crises in the river ecosystem does not exist, because, for an exchange of substances and energy in the river there is enough water. If CREF value is lower than the unit, then insufficient water flow is observed in the river.