Business idea - crayfish

The construction of an artificial reservoir for the cultivation of crayfish

The place for the construction of a reservoir it is desirable to select close from the source of water, as in case of his absence increases the cost of construction. The construction costs depend largely on the soil on the plot. The fat and the thin clay is the most reliable ground for all categories of ponds, as they are virtually impervious to water and slightly blurred. Heavy and middle loam is a firm ground for the pond. Light loams weakly overgrown with algae; their use for the construction of ponds possible, but with the use of additional means and methods of waterproofing bed of the pond. Clay and sands greatly miss the water, but may be filled with silt in the presence of the peaks and the slopes of ravines clay soils. In this case is the biggest waste of funds for the waterproofing of the bed of the pond. Thus, the basis for the construction of the pond is a water resistance of the lodge. Underlying soil resistant layers of a capacity of not less than 0.5 m must occur on all surface of a pond, and as close as possible to its shores and the surface of the earth. For the construction of ponds best suitable plots of land, on which there is a ravine, lowland or have you accumulation of water in the ditch his block earthen dam with a descent of water. Water availability not flow ponds depends mainly on the flood waters, spring, summer and autumn rains, as well as from permanent artesian wells or piped water.

Measurement of flow velocity and flow of water.

Educated groundwater streams, springs and keys in most cases it can provide a pond a constant inflow of water required running and water exchange. To determine the water flow need to set the current speed and width of the source. Measurement of the speed of water is conducted by way of the floats, which are thrown into the water, and note the time at which they are 20 m. The measuring is carried out several times in a quiet, calm weather. On the basis of these measurements to find the average velocity of flow between the point of the beginning of movement of the float and its end. Dividing the length of the land plot on the average time for completion of the float, find the average velocity of the surface flow, expressed in meters per second.
Exchange of water in the pond. The duration of water exchange in the pond depends on the mode, as well as from occurring in the water and soil the bottom of the basin of chemical and biological processes worsening gas mode pond. If necessary, increase or reduction of periods of water exchange should be guided by bandwidth descent of water, which depends on the diameter and the water level in the pond. And in flow-through pools of water are provided, usually of permanent water sources. In large farms, ponds and other facilities should be located on the plot in a certain sequence. For example, wintering ponds shall be placed as close as possible to water supply the pond, in order to reduce waterfall tray, for which it is difficult to take care of in the winter. In addition, at great length, tray stronger cooled water, coming to him in the winter pond. For growth ponds should be placed closer to the winter and royal, to reduce the distance transplantation of crayfish. Usually, however, household plots are not more than 10-15 acres, therefore on them it is difficult to organize a large one-time farm, and such individual households can manage one pond and several swimming pools for cultivation of freshwater crayfish.
The machine bed of the pond. At the selected place pegs noted the shape of the pond, if he is excavated on a flat terrain, and if his bed calculated on a ravine, it is noted place of platinum. In the flowing ponds for sewer pipes need to dig a trench in the middle of the bed with a chute to the dam, where it will be installed descent of water. As the bed of the pond should be impermeable to water, on the ground of light loam or sandy fit layer of small pebbles, mixed with clay, which is stamped by so that the bottom was the lowering of the planned descent of water. Then on top of lay a polyethylene film or toll, pour a layer of bitumen and, when he has hardened, it is applied a layer of cement mortar, mixed with the sand in the ratio of 3:1. Near the window of the weir to drain the excess water surface of the bottom is aligned, but the window of the effluent is inserted metal mesh, which prevents the exit of cancers of any age. The shore make vertical, which must be at 20-30 cm above the earth's surface and have an outside gentle descent. Brovka around the pond is done to ensure that in the event of heavy rain water does not get into the pond and is not contaminating the water. Around the pond you need to pour a layer of gravel-sand thickness of not less than 20 cm. Around the pond well planted trees and bushes, to improve its appearance and create near the shores of the shadow. The depth of the water near the shore should be no more than 30-40 cm.

The Dam

 For the dam of the water in the ditch or in a hollow apply the dam. It represents the embankment, built from the ground or other waterproof materials, across the gorge or valley. Spring or pound water, blocked off by a dam, accumulates, forming a pond. The size of the dam (height, width, slopes) depends on the depth and the area of the pond, the capacities of the local river runoff and other factors. The height of the dam could reach no more than 8-10 meters the width of the dam on the top of the ridge () makes not less than 3-5 m. The crest of the dam should be above the permanent water level by 1-2 meters. Wet slope (converted into the side of the water) the need to strengthen the turf, fence of brushwood, filled with stones, dry slope also strengthen the sod or seeded grass.

Organization of the weir for artificial water reservoir in the content of crayfish

Water drain

Water drain (from a pipe or bricks) to arrange at the level of normal water mirror or slightly below it, providing in such cases, the installation of the guards, regulating the discharge of water to maintain the necessary level of her in the pond, when there is a constant inflow of water. At the water drain establish the metal bars to the crabs do not departed from the reservoir together with the water. The cheapest, but less durable is the water drain, made of pine boards, but it is better to do it from the pipes, bricks or concrete. For draining the pond at the base of the dam arrange Water drain. Depending on the design of the distinguished panel, fitting, tube Water drains. According to the principle of differentiated bottom and siphon Water drain.

Bottom water drain

Bottom water drain simplified type consists of two main parts: the hive with the shutter and the". Lager - horizontal pipes laid under the dam, may be metal, plastic or reinforced concrete. Pit, or risers, is attached to 11 gutters with the open wall is made of concrete. For the full discharge of water, located in the pond, as well as groundwater, received by catchment channels of the drainage network lodge, the "threshold" hive lay at 10 cm below the bottom of the trunk of the ditch. In the construction of the bottom water drain need to see that in the places of connections of separate parts of it were no cracks and crevices through which could leave the water.

Such water drain used for the ponds constructed in the deep beams and ravines. Bottom water drain can be made in the form of a concrete pipe embedded in the body of the dam at the bottom of the pond. The hole of the bottom water draines pipe is blocked by wooden shield, moving in the slots of channels on an iron rod with a screw thread. Ponds for breeding crayfish is recommended to do with the area not more than 0.3 ha, so that we can arrange a weir and water drain in the form of pipes, arranged in a dam. Upper pipe should be laid at the height of the normal water level. Is it intended for automatic discharge of excess water. The lower the pipe is laid on the seabed for the full descent of water from the pond. From the dry slope of the dam both pipes are equipped with shutters and grilles with horizontal located rods.

The siphon water drain. For the discharge of water from notdrains ponds small area you can use the siphon water drain, consisting of separate pipes, laying across a dam or dams on the slopes and the crest of the ridge, to the output end of the installation was somewhat lower input. The input and output ends are fitted with closures, in addition, at the end of the input should be a fence made of metal bars to prevent falling into the siphon crayfish, fish, algae, etc. At the top of the siphon there are two openings-one for the release of air from the siphon, and the other to fill with water. They overlap the shut-off valves. Siphon water drains installation of asbestos-cement tubes of metal or rubber hoses. To catch crayfish from the pond it is desirable to arrange crayfishstops, placing them in a discharge channel. The site of the channel strengthen dern or concrete slabs, and in the end of the set stopes let the jumper covering the output river cancers of crayfishstops.

If the conditions of the area forced to build crayfishway pond above the water source (lake, river, creek), its edges dykes, and fill with water from a lake or river with the help of the pump or the siphon. Ponds, constructed for economic purposes plots near ferms, in their majority have no special devices for descent of water. But they can be successfully used for breeding crayfish. For this purpose, in the body of the dam there is a water drain or install the siphon water drain to ensure a complete emptying of the pond. After the descent of the water necessary to conduct land reclamation: clean the bottom of the debris, fill the holes and bumps, plan your bed and build drain network, if prior to that it was not.

The filling of the pond water

A pond it is recommended to fill in the late spring, when beginning to come in soil water, rich biogenic elements. First pour water ditches and deepening of the bed of the pond, while not logged soils of the lower layers, and only after that inundate the entire area of the lodge. In this way the quantity of nitrate nitrogen in the soil will increase by 2-3 times, thus exacerbate the process of aerobic (in the presence of oxygen) decomposition of organic substances. In other words, water is enriched with biogenic elements through contact with the ground. With the rapid same filling of the pond readily soluble compounds of nitrogen, phosphorus, potassium and calcium, which depend on the productivity of crayfishes agriculture of the pond, penetrate into the deeper layers of the soil and become inaccessible to phytoplankton. Most of the ponds usually have a slightly acidic water and bottom sediments.

River crayfish same feel better and grow in alkalescent environment. Therefore it is desirable to make from 3 to 20 t/ha of lime in the water or to fill the pond with water on a bed of it, depending on the acidity of the environment. The best results are obtained when making quicklime. Just dug on sandy soils ponds much is filtered, so their bottom need not only to lay a polyethylene film, but also put prepared impenetrable for water layer of soil thickness of 10-20 cm. Particular attention should be paid to drainage and water discharge, if the pond is flowing. The waterslide we have to put the grid of small-scale grid to prevent the departure from the pond of river crayfish.

A.I. Rakhmanov, "River crayfish. The content and breeding"