Hydraulic calculation of reliability and safety parameters of the irrigation network and its hydraulic facilities

Nowadays, more than 155.7 thousand km of irrigation networks are operated by WUA, farms and clusters. 95% of irrigation networks were built and commissioned in the 80s of the last centuries. The parameters of the irrigation canals, built in the 70-80s of the XX century, are set for irrigation of cotton and alfalfa irrigated agriculture during the growing season 170-210 days. Irrigation networks have been designed for this crop rotation scheme. Since 1993, the rotation scheme has changed to cotton-wheat. Irrigation networks began to operate continuously throughout the year after the transition of agricultural production to the cultivation of autumn cereals, which require irrigation from October to May. As a result, it has become difficult to carry out repair work on irrigation networks. In addition, irrigation networks have been designed, built and operated by adapting crops to traditional irrigation systems. In recent years, large-scale work has been carried out on the widespread implementation of watersaving technologies in agriculture.


Introduction
In particular, drip irrigation on 77.5 thousand hectares, sprinkler irrigation on 1.2 thousand hectares, pulsar irrigation technology on 2.0 thousand hectares and irrigation using flexible pipes (flexible hoses) on more than 200.0 thousand hectares are widely used, and furrow irrigation is carried out on more than 300,000 hectares. This method should lead to a reduction in the number of water resources used in agriculture, as well as a decrease in the amount of water taken from canals. However, if the amount of water taken from the source decreases, technical and technological problems related to the transportation of water resources in most irrigation networks arise [1].
One solution to these scientific and technical problems will be the construction of water intakes and dams for efficient water transportation in irrigation networks. It is a topical scientific and technical issue to deliver to consumers the sufficient and necessary amount of water through the canal by effectively selecting the distance between the dams. This section presents the results of research aimed at solving these scientific and technical problems.

Calculation of filtration losses in the canal
In many cases, the method of filtration resistances is widely used in engineering calculations on a large scale to make them suitable for calculating filtration in the formation of complex flows in canals and other structures.
The basic principles of the filtration resistance method are described below. It is characterized by the possibility of replacing correctly formed boundary conditions at a certain distance with the boundary conditions of the part, which is similar to the state of the filtration water flow rate and the general view at a certain distance under conditions of a sharp change in the filtration pressure. As a result of this replacement, abrupt changes in flow are eliminated, and a flat-sized flow is formed with pressure distribution up to the formed waterproof layer. It possible to efficiently calculate the filtration processes occurring in irrigation systems, canals, reservoirs and hydraulic structures.
The execution of computational operations by the filtration resistance method is based on the hydraulic solution of problems obtained separately with the parameters obtained from laboratory and field experiments. For example, when considering filtering in a canal, the filtering current is replaced by boundary conditions that take resistance into account.
When calculating a stable filtration process, the specific water flow in one direction in the canal is determined as follows: (1) formula: T is average water permeability, m 2 / сут; k h is difference between canal and groundwater level, m; k Ф is filtration resistance pressure depending on the hydrodynamic state of the channel, m; п  is evaporation rate of water. The formula for calculating the specific flow rate of water for filtration when filling the canal itself with concrete is as follows: Formula obl Ф is additional resistance arising when the canal core is poured with concrete, m using the following phrases, we get: Additional resistances caused by coatings in the canal are calculated using the following formula: The groundwater level around the canal is determined by the following formula: when the channel core passes through the ground The following parameters are used to calculate the filtration rate according to (6) or (7), if there are different soils in the two layers of the channel: Calculation of filtration in a concrete-lined canal in motion mode. The following formula is recommended for the flow rate of one-sided specific filtration when the canal core is filled with concrete.
Calculation of the state of reliability of an irrigation canal.
When using canals, it is important to assess quantitative indicators of the state of reliability associated with such adverse effects as wear of canal dams under the influence of dangerous filtration currents, subsidence, and elevation of canal sections relative to the area.
The use of the Bayesian method to quantify the reliability of irrigation canals yields good results. In this method, based on field experimental observations and statistics, a diagnostic hypothesis can be selected with a high probability, which allows the system to assess the state of reliability.
Bayes' formula is: where: Three main diagnostic indicators affect the reliability and safety of risers: K 1 is location of the canal dam above the water level; K 2 is collapse of the canal dam; K 3 is filtering gradient from the base and body of the canal.
Taking the above into account, the issue was resolved as follows: Based on the above diagnostic parameters, the following was determined:

  P A B P
The probability of an accident as a result of a breakthrough of a canal dam is determined: As a result of calculations made based on data on the tributaries of the Upper Mamurabad canal, it should be noted that the reliability of the aboveground part of the canal is normal. The probability of an accident as a result of a canal dam break is 0.61.

Results and Discussion
Hydraulic calculation of the length between dams in concrete and soil ditches, taking into account the filtration, evaporation and technological costs of water in the process of transportation of water resources through the irrigation canal, as well as the required efficiency of irrigation canals. The research object is the interval between № 8 and №9 branches of the Upper Mamurabad canal in the territory of Karasuv WUA of the