Alimdjanov A.A., Horst M.G., Pinxasov M.A.

In recent years, the previously existing organization of irrigated lands has been divided into many farms with relatively small irrigated areas. Against the backdrop of the widespread use of gravity irrigation from gravity irrigation systems in the region, these water resources have become more difficult to manage at the lower level - the Water Consumers Association (AVP).

The main purpose of establishing AVP as an institution is to ensure the fair distribution and efficient use of water resources among water users. However, at the same time neither fair distribution nor efficient use. One of the reasons for this is the principle of water management within AVPs among water users.

How is the water distribution now organized within the AVPs?

Currently, water users are using the traditional ten-day water distribution planning method. This methodology focuses on large units of water use (50-150 ha) in which the water consumer (usually a community) is planned to provide water with a direct flow. Based on the accepted norms for irrigation of certain agricultural crops for certain areas (hydromodular areas), the consumption of a certain amount of water in a certain period of time is calculated - l / s / ten-day ordinates of irrigation hydromodules measured with e. Now the calculation is also carried out: the total area of the contours within a single AVP, the number of hectares occupied by individual crops, the level of water consumption for each crop, how much water is needed for each crop. individual AVP. This calculation is then agreed with the Canal Authority, after which an agreed seasonal water use plan is adopted, taking into account the estimated availability of water. This method takes into account the total, ie. How much water is usually needed for all AVP water users.

However, this method does not take into account the fact that in modern AVPs there are many farms (FHs) with relatively small contours of irrigated areas, each FH is in fact an independent unit of water use. Thus, the principle designed for large contours of large farms applies in the same way to a set of small contours of individual farms.

But this method works very inefficiently for many private households. There is a problem with the spread of small irrigation streams to many sectors of the farm along the farm's irrigation schemes. Simply put, the AVP receives a limited amount of water, which it calculates to lead to large contacts with direct current, but because the water spreads to many irrigation ditches inside the AVP and less to each branch amount of water flows (see Scheme 1). And a limited amount of water reaches every farmer. If a farmer irrigates his field with enough water for 1-2 days with a small amount of water, the irrigation period can be extended to 10 days or more.

As a result of such distribution of water supply, water losses in the on-farm irrigation network between irrigation schemes increase many times. Such a water supply scheme also causes every farmer to try to enter the water by any means - they open the doors without permission, steal water passing through its scheme at any time if there is water in the canal, water remove. channels at night with pumps. Such unauthorized use of water leads to excessive water wastage by some farmers (at the beginning and middle of the canals) and by other farmers (at the tail of the canals).

How can irrigation be organized in an alternative, more efficient way?

The shortcomings of the traditional method can be overcome by introducing a daily planning method of water distribution through a concentrated water supply to end users. This method was developed, tested and proposed for further distribution at the Scientific Information Center of the Interstate Coordinating Water Commission (NIC MKBK).

The calculation of water consumption remains the same with daily planning, but water is supplied to each water consumer in turn according to the previously submitted applications of each of them. Technically, this can be done very simply: in the SFU’s irrigation network, a mirab (hydrometer) closes or opens one or another branch to provide water to one or two farmers in a continuous mass. The water is then supplied to other outlets, and the rest of the water supply is turned off. These are. water will be delivered to all farmers / water consumers in the required quantity in series according to the requirements. So, the farmers are located along the AVP canal and regardless of the size of the field, it receives water according to its priority (on request) depending on the needs of the irrigated area. Such a water supply regime is very satisfactory for AVP employees and water consumers, who know in advance to whom, when and at what rate to supply water. Here, the role of the AVP mirab (hydrometer), which must be followed in the water supply sequence, is enhanced (see Scheme 2).

The impact of the transition to alternative daily water distribution planning

In most cases, all internal networks of the SFU have a ground bed. Losses for infiltration and irrigation techniques range from 20 to 51% of all water, according to various estimates. With the traditional irrigation method, water is supplied simultaneously through all branches of the SFU irrigation network. With the proposed alternative, water flows only through the open branches and leaves the rest of the network without water. In other words, water flows along a smaller length of canals within the network, with alternative daily planning. This means that the losses for infiltration are much lower.

This method was tested on the Singir-1 canal in S. Kasimov: “In Bulakbashi district of Andijan region. With daily water distribution planning, the length of the irrigation network supplied by the average water supply during the growing season was 55% of the total length of the irrigation network. The results are presented in Table 1.

Table 1 - Water distribution indicators for dispersed (ten-day) and concentrated (daily) water distribution along the Singir-1 canal system.

Comparing the two options of water distribution, the water supply to crops with a concentrated water supply will be higher than with a conventional water supply.

The average water supply at the level of the outlets of irrigated arable lands to the volume of water supply to the terminals of water supply terminals of volumes corresponding to the norm of water consumption (pure norm of irrigation according to the irrigation regime) determined by the ratio. irrigation network.

According to Table 1, 1632.1 thousand m3 of water was supplied to the branches of the Singir-1 system deposits with dispersed water supply, ie. the volume corresponding to the watering rate - exactly, including:

• for cotton - 6200 m3 / ha

• for winter wheat - 5300 m3 / ha

With a concentrated water supply, 1850.5 thousand m3 of water was delivered to the fields of the Singir-1 system. the volume exceeding the net irrigation norm and consists of:

• for cotton - 7029 m3 / ha (more than the norm 825 m3 / ha)

• for winter wheat - 6009 m3 / ha (more than the norm 709 m3 / ha)

In the Fergana Valley, according to our data, the average efficiency of furrow irrigation is 70% [1], and the average water supply to irrigated fields is:

• with diffuse (ten-day water distribution planning) water supply - 70%

• with concentrated water supply (daily planning of water distribution) - 79.4% (for cotton - 7029 m3 / ha / 6200 m3 / ha * 70% = 79.4% and for wheat - 6009 m3 / ha / 5300 m3 / ha * 70% = 79.4%)

To determine whether productivity depends on irrigation norms, V.R. Schroeder [2] used the method of relative expression of the values of productivity and irrigation norms. The corresponding value of the maximum yield and irrigation rate is taken as a unit. The ratio of the net irrigation norm to the gross irrigation norm at the level of the fields planted is equivalent to the availability of water.

Based on research in the Central Asian region, the dependence of the crop on water availability was determined by V.R. The shredder is in Table 2 form.

Table 2 - Dependence of productivity on water availability

A For the zone where the VP is located, “S. Kasimov ", (according to the indicator areas of the project" IUVR Fergana ") known [3] values of the maximum yield: for cotton - 40 ts / ha and for winter wheat - 50 ts / ha. and based on the values in Table 2, calculations were performed to determine the yield based on the actual availability of water (see Table 3).

Table 3 - Results of the calculation of the growth of crop yields due to the increase in water supply compared to the distributed water supply option (ten-day planning)

Taking into account the effect of increasing the water supply of major crops (cotton and winter wheat), the calculation of the cost-effectiveness of daily planning of water distribution on farms was carried out, as well as on the example of irrigated lands. Singir-1 channel (Table 4).

Table 4 - Results of calculation of cost-effectiveness of daily planning of water distribution (concentrated water supply to farms)

Note: As of 15.11.11 of the Central Bank of the Republic of Uzbekistan - 1 US dollar = 1769,285 soums

Planning the water distribution on a daily basis provides an important opportunity to organize irrigation: start and end the watering of the furrows and replace the cost of irrigating the next irrigated areas only during daylight hours.

Thus, the results of the introduction of daily water use planning show the following possibilities:

~ Increase the efficiency of in-farm irrigation networks of AVPs by 10-15%;
~ Therefore, increase the water supply of the main PC without additional water from the main canals;
~ increase productivity due to increased water;
~ increase profits by an average of $ 69.8 / ha (including: $ 96.2 / ha for cotton and $ 43.1 / ha for winter wheat).
~ reduction of water intake from main canals by 25-35%;
~ equal and timely distribution of water resources among all water consumers;
~ reduce social tensions between water users and AVP staff over late delivery of water and its unfair distribution among SFU users;
~ Maintain soil fertility and expand reproduction.

BOOKS

1. Horst M.G., Shamutalov S.S., Pereyra L.S., Gonkalves J.M., Fergana, Field assessment of water-saving potential of irrigated agriculture in the Aral Sea Basin. Water Management 77, 210-231 (2005)
2. Shreder V.R., Vasilev I.K., Trunova T.A. - Calculation of hydromodular zoning and irrigation norms of cotton in the arid zone. SGVH and SANIIRI Collection, No. 8, Tashkent, 1977, pp. 28-44.
3. Nerozin S.A., C1.1 report - "Detailed study of aspects of financial and economic feasibility of IUVR organizations", "IUVR Fergana" project, ICWC SIC, Tashkent, 2010.
4. Pinxasov M.A. - “Guidelines for setting tariffs for water supply organizations
water user services ”,“ IUVR-Fergana ”project, Tashkent, 2009.

If you have any questions about the introduction of the technology, please contact the Scientific Information Center of the Central Asian Interstate Commission for Water Coordination (NIC MKBK).

Republic of Uzbekistan, 100187, Tashkent, Karasuv-4 massif, 11
Phone: (998 71) 265 92 95, 266 41 96
Fax: (998 71) 265 27 97
E-mail: dukh@icwc-aral.uz
Director: Doctor of Technical Sciences, prof. Dukhovniy Viktor Abramovich