Пространственно-временная трансформация грунтового комплекса водохранилищ Волги. Сообщение 3. Оценка изменения морфометрических характеристик в результате накопления донных отложений в Угличском водохранилище.

Abstract

Comparison of assessment methods of the reservoirs’ hydro/morpho/metric characteristics changes due to accumulation of bottom sediments and abrasive/erosion processes have been done. The results of the Uglich reservoir bottom sediments monitoring have demonstrated that the morphological/metric characteristics practically have not changed over the 70-yeat period of the exploitation, the Kalyazin lake/river area being the only exclusion. The areas with the transformed soils left as they were, while the areas with sand drift decreased, the areas with clay sediments decreased, and wetlands appeared. Spits, sand-bars, sprinkles and banks that divide a part of water area have been formed at open shallow sites and river mouths. The reservoir hydro/ morphological /metric characteristics have been assessed by the results of monitoring soil surveys in situ, that is, by direct measurements of the bottom sediments thickness and by the bottom topography digital model that had been carried out independently in the Institute of Inland Waters Biology and State Oceanographic Institute. Over the whole period of the reservoir exploitation 28.6 million m3 of bottom sediments have been accumulated, while the water volume loss was 22 million m3. The discrepancy was about 0.6 %. Both methods have given good results and are entitled to further use in researches. Deposits distribution has been mapped. Sedimentation volumes and rates have been calculated, suspended matter balance has been produced, and situation forecasts of the main ground types and bottom sediments formation ways have been made by the 100the anniversary of the reservoir exploitation.