ХАРАКТЕРИСТИКИ ПРОСТРАНСТВЕННОГО РАСПРЕДЕЛЕНИЯ ГИДРОЛОГИЧЕСКИХ И ЭКОЛОГИЧЕСКИХ ПОКАЗАТЕЛЕЙ РЕЧНОЙ СЕТИ РЕСПУБЛИКИ МАРИЙ ЭЛ

В статье рассмотрены эколого-гидрологические характеристики и система мониторинга водных объектов Республики Марий Эл. На основе сформированной базы данных определены параметры речных бассейнов: густота речной сети (варьирует от 0,18 до 0,85 км/км2при среднем значении 0,47 км/км2), залесённость (от 2 до 90 % при среднем значении 57 %), среднегодовые сбросы сточных вод в водные объекты (56 млн. м3) и на водосборные площади (6 млн. м3). С использованием ГИС-технологий построены региональные тематические карты актуализированных гидрологических показателей речного стока (модули среднегодового стока, стока весеннего половодья и стока летне-осенней межени; максимальный слой дождевых паводков); размещения пунктов мониторинга и объектов негативного воздействия на водотоки и их водосборные площади. Установлено, что наибольшую нагрузку испытывают верховья и среднее течение рек Малой Кокшаги, Илети, Немды и Уржумки, бассейны рек правобережья р. Волги. В составе загрязнителей преобладают хлориды и сульфаты (84 %), взвешенные (9 %) и органические вещества (по БПК – 6 %). Мониторинг истоков рек показывает стабильные превышения нормативов качества воды по содержанию марганца, меди и железа.
Introduction. Against the background of climatic changes, an updating of hydrologic characteristics of the regions takes on special significance both for the support of agriculture and construction, and implementation of environmental protection measures. The goal of the research is to develop an updated special database of hydrologic, orographic and monitoring data in order to assess the spread, runoff and quality of Mari El surface waters using GIS technologies. Research methods. The basin approach method, cartographic method of analysis of qualitative and quantitative characteristics of environment, thematic mapping with the use of GIS technologies were used for the research. Results and discussion. First, an analysis of factors for surface water formation in the research region was carried out. Based on various manuals on basins of major rivers of the region, a database of hydrologic and ecological data was developed. The drainage network density in the region is on average 0.47 km/km2 ( the lowest rate is in the basin of the Parat, 0.18 km/km2; the highest rate is in the basin of the Malaya Yunga, 0.85 km/km2). The forestry area in the river basins varies from 2-7% (basin of the Yunga, the Malaya Yunga, the Nemda) to 85-90% (basin of the Rutka and the Parat). Annual discharge of sewage waters into rivers is 56 mln. m3 (more than half of sewage waters are released into up- and midstream of the Malaya Kokshaga) and about 6 mln. m 3 are released in the basins (mainly, the Malaya Kokshaga and the Ilet). Of the contaminants, chlorides and sulfates prevail (84%), suspended matters take 9% of all contaminants, organic matters - 6%. With the use of GIS technologies, regional thematic maps of updated hydrologic data of river runoff, distribution of monitoring facilities and facilities of negative impact on the runoffs and their basins were generated. The value of average annual local runoff is on average 5-6 l/(s·km2), maximum figures are observed in North-West and South-East of the region (7-9 l/(s·km2)). The unit runoff rate in spring flood is mainly 100-150 l/(s·km2), up to 250-300 l/(s·km2) in South-East of the region. Minimum runoff in estivo-autumnal low-water level is 1-2 l/(s·km2); maximum layer of rainfall flood with 1 % exceedance probability for almost all the region is 30-50 mm. Conclusion. A geo-information system describing a river net of Mari El was developed. It was demonstrated that upper and middle reaches of the Malaya Kokshaga, the Ilet, the Nemda, the Urzhumka, and basins of the rivers of the right bank of the Volga were under the highest load. The surface waters quality is found to be of impact (releases of waste plants) and diffusive (releases from agricultural lands, populated localities not in the system of centralised canalisation as well as enterprises and institutions, releasing wastes in the local area) pollution. Natural factors have a significant impact on the normative quality of waters.
ВЕСТНИК ПОВОЛЖСКОГО ГОСУДАРСТВЕННОГО ТЕХНОЛОГИЧЕСКОГО УНИВЕРСИТЕТА. СЕРИЯ: ЛЕС. ЭКОЛОГИЯ. ПРИРОДОПОЛЬЗОВАНИЕ, Выпуск 4 (48) 2021, Pages 61-76