SU853000A1 - Method of protection against water pollution in canals - Google Patents

Description

Provided that, 25 T, there will be a leakage of groundwater under the drain.

Provided that 0 T, the filtration flow is completely formed in the thickness of the permeable base throughout its thickness, and therefore a further increase in this distance is impractical and leads only to a higher cost of the method due to an increase in the occupied area of agricultural land.

The difference in water levels in drains, the position of the depression curve and the distance between drains in the range of (0.25-2.0) T are determined, for example, using the EGDA method, since there is no leakage of groundwater flow to drain 3 and channel 1.

The drain 3 is filled with clear water, for example, from channel 1, and the drain 4 is sunk so that the water level at maximum filling is below the water level in drain 3.

With this arrangement, drains 3 and 4 with respect to channel 1 of the streamline current flow of clean water from drain 3 are directed toward drain 4, creating a countercurrent in the entire water-permeable stratum from drain 3 to roofing that prevents the flow of ground water to the channel.

In the case when the water level in drain 3 is higher than in channel 1, part of the filtration flow from it is directed into the channel, completely preventing filtration of water from the channel.

In the case when the water level in drain 3 is higher than in the canal, the filtration flow from the canal is directed toward the drain 3 and can get into both drain 3 and drain 4, preventing the movement of the contaminated groundwater flow.

In both cases, the flow of groundwater (see arrows B) under the action of a filtration current directed towards it from drain 3 (see Fig. 1) or from channel 1 and drain 3 (see Fig. 2) enters drainage 4, where and stormwater flows.

This method completely eliminates the overshoot of the polluted flow of groundwater under imperfect drainage 4 over the entire permeable stratum of the soil both into drainage 3 and into channel 1, preventing contamination of water in the canal.

For each of the above cases, a different nerepad is established between drains 3 and 4, which prevents the pollution of water in the channel by the ground flow. For

Ensuring minimal irretrievable losses of clean water on filtration during seasonal changes in groundwater inflow and channel level changes the water level in drain 3 accordingly, maintaining the minimum necessary excess above the water level in drain 4.

For example, with an increase in the water level in channel 1 and a decrease in groundwater inflow (or their pressure gradient),

the water level in the drain 3 is reduced, thereby reducing to a minimum the filtration flow from the drain 3 to the drain 4.

The method allows to ensure reliable protection of water in the channel from contamination during

small, in comparison with known methods, the depth of both drains. This is due to the fact that the first drain may be located above the water mark in the channel; The latter circumstance significantly reduces the capital cost of the implementation of protecting the channel from soil contamination.

Claims (2)

1. Acce. for Japan № 47-48736, cl. E 02B 9/02, 1972. 2. Romanov A.V. Filtration calculation methods for drainage facilities. Questions filtration calculations of hydraulic structures, M., 1959, p. 102-103. Udh at 1