Theoretical basis of water sustainability of arid areas in the south of Uzbekistan

Topicality and relevance of the dissertation theme. Water is the main limiting strategic resource in arid areas that determine the development of all sectors of the economy. Addressing issues of water supply has become an essential and complex contemporary scientific-technical problem, as «...coming to 2030 global deficiency of water resources in the planet will reach to 40 %...Global consumption of water in 2050 will increase up to 55 % »'. Population explosion and intensive development of economy intensifies shortage of water resources. Especially, that applies to areas with limited natural water resources where stable development depends on water transboardcrcd rivers.
In this regard, during the years of independence, the leadership of the Republic of Uzbekistan adopted a number of decisions to address the urgent problems of the country. «Water is considered as one of the main causes of climatic changes. Fighting against escalating risks and uncertainties of natural disasters is essential for elaboration of methodic and effective mechanisms of regulations»
With climatic global changes, development of advanced technic solutions for improving hydroccologic and meliorative-hydrologic conditions of irrigated lands in arid areas is required, including modernized technologies and methods of managing dynamics of moisture and salination conditions in aerated zones, subirrigation, water demineralization and soil melioration, principles of struggle against salination and erosion on the bases of complex experimental-theoretical analysis and forecasting main irrigation tendencies, that arc needed for practical usage by irrigational and agricultural organizations.
This dissertation research serves as fulfillment of tasks, listed in the Decree of the President of the Republic of Uzbekistan (№ UP - 3932 of 29.10. 2007) «On measures on radical improvement of land reclamation», the Decree of the President of the Republic of Uzbekistan from 19 april 2013 № PP - 1958 «On measures of further improvement of irrigated land and water management for the period 2013-2017, » Resolution of the Cabinet of Ministers R. Uz from 20 may 1999 № 259 «On holding irrigational-mcliorative works for the period of 1999-2000», from 21 july 2003 № 320 «On Improvement of Water Management», from 19 march 2013 № 82 "On Approval of the order of water use and consumption in the Republic of Uzbekistan" and other standardizcd-lcgal ducumcnts, accepted in this field.
Purpose of research is to develop waterproof hydroccologic technologies and meliorative-hydrologic methods.
The scientific novelty of research is as follows:
enhanced the principles of the creation of anti-filtering screen at a given depth of groundwater;
scientifically proved through sub-irrigation development of devices for controlling runoff and drainage schemes «Cascade»;
proposed water saving and soil-protective method, preventing irrigation erosion in flat gypsum soils;
for the first time recommended chemical meliorants, depressing soda salinization of soil with forming effective fertilizing- chili saltpetre;
developed metods of water demineralization;
suggested the technology of increasing efficiency of precipitation, irrigation and groundwater plants, which in-leads to the prevention of negative phenomena, improve productivity and increase the aeration zone energy (exergy);
CONCLUSION
1. Strategically-limiting nature of the region's water resources is justified by theoretical analysis of a representative period, the priority of water management characteristics of mathematical statistics, which confirms the correctness of the differentiation of natural water conditions and is the first experience of area-regional zoning in modem terminology. It is a type of application and geographical regionalization is to allocate natural water complexes (PVCs), considering historical administrative boundaries with a single natural base, which revealed new negative hydro-ecological and hydrological processes, to develop a set adaptive solutions for each upgraded PVHR.
2. Proven fundamental theory of metamorphism chemical composition of water to predict the state of irrigated lands of the arid zone. Updated formed ionsalt composition of water resources in the region. It is shown that metamorphism chemical types of groundwater well consistent with the types of soil salinity (at V.A.Kovda et al.).
3. The basic laws metamorphose waters in the region, which grow in the opposite direction (leaning toward hydro carbonate type) in the following order: surface water and groundwater PVHR upper- middle PVHR groundwater and sub - bottom PVHR groundwater. This was the theoretical basis for the projections of a new salinity (alkalinity) of soil at watcring-NII. It was found that the local areas may receive soda salinity in the above manner (3-5 years), t. E., To the geographic shift hydrocarbon groundwater in the southern and south-western directions, which is a form of modem desertification areas.
4. Substantiated the fundamental meaning of the "critical depth interval of occurrence of GW on the main reclamation - hydrological factors - groundwater salinity. Experimental and theoretical method developed principles for the determination of the NKR.
5. It was revealed that a qualitative change in the composition of the salts in the aeration zone by prolonged leaching irrigation regime on the background and the natural drainage leads to increased removal of non-toxic salts. This process is activated by leaching calcium sulfate (gypsum), which prevents the development of processes of alkalinity. In this connection it is necessary to change the ideology of drainage systems through the introduction of sub-irrigation technology in the range of 2 - 3 g /1 total mineralization GW.
This allowed for the first time the arid zones of the region to develop a modernized devices to regulate the drainage flow in order to introduce subirrigation through groundwater management by sticking to the depression of the curve in the range of the critical depth of the GW. We also propose the optimal formula for calculating the cascade devices. These facilities arc also recommended to arrange for sprinklers and river network.
6. An ecological and economical way of water demineralization, Ba-vanny on gas hydrate technology as one of the fundamental solutions to the water problem by preserving and protecting the resources of fresh surface water and groundwater in the arid zone by utilizing miner-ized water (2 - 3, 200 - 300 g /1).
7. Developed a method of soil desalinization chemical amcliorants it solves the dual problem of reclamation - soda salinization and suppresses the formation of nitrogen fertilizer blends (Chilean nitrate NaNO3).
8. In order to improve reclamation- hydrological conditions of local zones of aeration is provided a method of isolation of groundwater within the hydrogeological windows to prevent flooding (or draining) and salinization, which is due to thinning (or infiltration) mineralized GW in irrigated areas.
9. An analysis of experimental and theoretical studies Mclio-way radio has reduced the soil's physical and productive increase evaporation (transpiration), to improve the conditions of hydro-aeration zone, increase drought tolerance, overall biological activity, energy capacity, connectivity and productivity of soils.
10. Sound technologies subirrigation, demineralization and grind-orations contributes to accomplish the total water circulation technology in the scheme of complex use and protection (integrated management) of water.
11. Theoretical and field studies revealed patterns of irrigation erosion in flat gypsum soils. Designed upgraded method of combating comprising conjunction with the sowing of crops convolutions making up the bottom of the cutting grooves on the surface of the natural soil amcliorants (together or separately) - expanded vermiculite and firing (or) perlite and montmorillonite, bentonite and kaolin.
12. Identified patterns and results of this work should be considered identical subarid parts of the world.