Study of the role of natural and anthropogenic factors in the formation of water quality in small rivers on the example of the Veletma river in the Nizhny Novgorod region

Small rivers of Central Russia often experience a high anthropogenic pressure, and at the same time their study measures taken to preserve them are incomparably more modest than for large rivers. On example Veletma river in Nizhny Novgorod region, factors affecting formation water quality small considered. The ecological geographical characteristics given. It is shown that current methodology assessing by Specific Combinatorial Water Pollution Index does not allow determine what contribution pressure deterioration quality, natural factors. Studies number physical chemical waters have on short section river, which less 400 m, there significant changes composition water, reaching 45-95%. Such associated one hand with influence treatment facilities city Navashino, other hand, special location lake Zelenoe path river. Satellite images Veletma's confluence show plume. suggested characterized processes take place medium-sized into seas lakes, called marginal filter, only suspended but also dissolved impurities retained. This fact confirmed laboratory studies.