CC BY
0GEOGRAPHICAL SCIENCES
ASSESSMENT OF WATER RESOURCES AND RISK OF WATER LOSSES DUE TO CLIMATE
CHANGES AND HUMAN ACTIVITIES
Mammadov R.
Director of the Institute of Geography Azerbaijan National Academy of Sciences, President of the Azerbaijan Geographic Society, academician, professor
Teymurov M.
Leading Researcher of the Department of Surface-water Hydrology and Water Resources, Institute of Geography of Azerbaijan National Academy of Sciences
Abstract
A new methodology is offered for assessment of the water resources and water balance elements, risks of water loss, determining the percentage of climatic changes and human activities separately. The calculations can be performed in a simple, readily and high-precision way with LULC (Land-use va Land cover) and meteorological (precipitation and temperature) data independently of spatio-temporal variations. It is intended 3 stages of study. At 1st stage, analysis of the past condition of water resources of the territory is studied (previous-investigation), the 2nd contemporary situation (current-investigation) and the 3rd covers the forecasting studies in the future (forthcoming-investigation). The connection of the stages studies outcomes gives reliable results for current investigations and facilitate to forecasting in future. Unlike previous studies, when calculating and forecasting water resources and its loss risks, not only climatic, but also human activities (LULC) changes are taken into account. Both the obtainment of LULC data with multispectral analysis of satellite images, and carrying out prediction with different climate changes models (GCMs) gives a high reliability to the received results. The studies carried out over 29 river basins show that the errors between the observed values and those obtained by the proposed method are very little and the percentage errors of 22 rivers from 29 around are ± 10%. For example, the results of studies over water balance elements and risks of water losses in the 14.5 km2 area for 1963, 2016 and 2050 years are provided. The water resources of the territory were estimated 5.65 mln.m3 for 1963 and 6.70 mln.m3 in 2016. In comparison with the background rate of 1963 year, the water resources of the territory in 2016 year increased +16.25% and this is related to +9.57% with anthropogenic impacts and +6.68% with climatic changes. The predicted water resources for the year 2050 due to different climate forecast scenarios and LULC changes are also defined (mln.m3): 6.36-CCCM model, 6.58-GiSS, 6.85-HadCM3, 6.98-GFDL-3, 7.22-ECHAM5 and 6.76-UKMO. Compared to 2016, in the context of -5.35% decrease water resources in 2050, the share of the influence of human activities consist of +5.06%, but climatic factors were -10.41%.
Keywords: water resources, water balance, risk assessment, LULC, human activities, multispectral analysis, climate changes models
Introduction
The estimation of water balance elements is frequently needed for water resource planning and environmental impact analysis. Among the most basic challenges of hydrology are the prediction and quantification of catchment total runoff and water resources of any territory. Remote sensing and GIS can be effectively used to manage spatial and non-spatial database that represent the hydrologic characteristics of the watershed. The global climate changes, especially in the context of decreasing precipitation, creates a negative role in the formation of runoff in individual areas, as well as a significant impact on the variability of water resources. Modern scientific approaches related to water issues require not only a continuous study, in parallel challenges the estimation with a new, modified and sensitive to the natural and human changes methods. The main advantages of these methods, which preempts traditional ones, should be a gradual decrease in their dependence on the duration of a series of observations over the runoff and the expansion of the functions of determining an element based on GIS technologies and satellite images.
Our research is based on the synthesis of the positive aspects of the world's most popular and proven methods for determining the water balance and our
results in this study area. The proposed method allows to determine elements of the water balance in case of spatio-temporal changes of any territory, as well as when the area is constant, to follow climate, landscape and land-use changes and determine their influence on the water balance elements, and by comparing different periods, it is possible to predict the state of the water balance in the future.
The carrying out of these studies is expected to fulfill in three stages.
1. The analysis of antecedent humidity conditions, water balance and water resources of the territory (previous-investigation).
2. The analysis of contemporary nature and water balance state of the territory (current-investigation).
3. The prediction of water balance and water resources based on future changes (forthcoming-investigation).
The connection of the stages studies outcomes gives reliable results for current investigations and facilitate to forecasting in future.
This methodology is very important from the point of view of solving many problems of hydrological science, such as determining water balance and water resources, assessing the role of climatic and anthropogenic factors and the share of influence of each element
separately. At the same time, carrying out these works when using space images does not depend on the availability of basic data in any given territory.
Short description of the applied methodologies and used materials
When assessing the water balance of the territory, various methods were used by us. In the post-Soviet space, the most popular method was the Lvovich method [17,47,48]. But in the US and Western countries the most important methods in this sphere are the Rational method and the Curve number method.
Lvovich method. In this method, the water balance of a territory is characterized by 4 constituent parts: 1) Atmospheric precipitation (P), is the water fallen on the territory from clouds and it is the main incoming element in total water balance.
2) Actual evaporation over territory (E), is the fraction of wetting returned to the atmosphere as water vapor.
3) Baseflow (U), is the supported portion of the feeding of streamflow that comes from deep and delayed shallow subsurface flow in dry period (in non-precipitation events). It is the stable part of streamflow.
4) Total river runoff (Qt), consisting of surface (Qs) and underground (U) parts: Qt = Qs + U.
According to Lvovich, annual precipitation can be separated into two components:
P = Qs + W, in Qs - surface runoff, the fraction of runoff originating on the land surface and W- is catchment wetting, the fraction of precipitation not contributing to surface runoff. The catchment wetting separates into below components: W = P - Qs = U + E
Between the elements of water balance there is a relation as P = Qs + E + U.
Rational method. The rational method allows to determine the rational (surface) runoff coefficient based on the LULC, the soil texture and the slope of the territory, and using the amount of fallen precipitation on the given territory and its area, determine the runoff discharge and water resources by the formula Q =k x ciA.
Where, Q-surface runoff discharge, in m3/sec.; i-the rainfall, in mm; c-rational (surface) runoff coefficient; A-The drainage area, in km2; k-transition coefficient for converting the surface runoff discharge by unit m3/sec. (k=0.0000314).
The popularity of the rational method is its convenience, simplicity, predictable, a long history of researches, to pass the modification development ethape, reliable genesis and other factors. The rational runoff coefficient (c) is an parameter used in hydrology for predicting direct runoff from rainfall excess and to assess the level of surface runoff-forming after rainfall. The rational runoff coefficients are parameteres depending on the soil granular structure, LULC (Landuse & Land cover) and slope degrees, etc.
Previously, this method was used in the study of urban hydrology and the peak discharge for small river catchment [4,16]. Gradually, the method was improved and modified, and at present its application is possible in the study and solution of the following issues of hydrology [6,10,15,36]:
— The mechanism and conditions of the runoff generation, the relationship between rainfall and surface runoff.
— The floods and peak discharges.
— The time concentration of runoff over the catchment area.
— The urban hydrology and determination of the urbanization impact on runoff.
— Use of water resources in water management activities, engineering, etc.
USDA methods. These methods, in addition to surface runoff, also make it possible to determine the water balance elements reflecting the soil moisture content [11,12,27,28,29,43].
1) Hydrological losses (or hydrological abstract) - the fraction of precipitation that does not participate in the formation of surface runoff (or the total value of infiltration and evaporation). It is denoted by L and is estimated by the formula L=P-Qs, where Pis precipitation and Qs-is surface runoff.
2) Maximum retention (or maximum soil retention) — is the potential maximum soil moisture retention after runoff begins in a specific physio-geographic condition and is denoted by S. In other words, this parameter show the maximum water retention which can be used to moisturing of the territory in available geographic and climatic condition, and is considered a key factor in terms of the water balance. A relationship between this element, precipitation (P) and surface runoff (Qs) is expressed thus: S = 5 x [ P+2Qs - (4QS2 + 5PQS)% ].
2) Initial abstraction — is part of the rainfall spending on various areas before the formation of surface runoff and denoted by Ia. It serves as a preparatory stage in the transformation of precipitation into surface runoff. Initial abstraction-is the fraction of rainfall, which spent to water losses as infiltration, primary evaporation and transpiration, detention and depression storage, interception on the plant canopy, soil moistening, etc. before runoff begins.
3) Actual soil moisture (F) - is factual soil retention after rainfall in concrete geografhical location, it's in the form F=P-Q-Ia.
Each of these methods have passed a long path of research, with strong genetic bases and are highly accurate. The synthesis of a number of main features of these methods makes it possible to determine the water balance and water resources in a more accurate and less labor-intensive way. The rational and curve number methods are supported by leading organizations on water and natural resources of the United States, as well as by UNESCO and FAO. In recent years, with the support of international organizations, the water resources of several countries with water shortage have been determined by these methods [1,2,3,5,14,18, 20,21,31,32, 35,40,41,42].
The data information on rational runoff coefficients and curve numbers are collected in hydrological manuals and handbooks during many years [13,23,25,37].
When the 3 main components of the precipitation (surface runoff, baseflow and evaporation) were assessed, we proposed a combined method in context and taking into account the positive characteristics of the 3 known method of the world. It is possible to estimate the total runoff of rivers (summation of surface runoff and baseflow) with synthesis of the Lvovich, rational and curve number methods offered us methodology. The surface runoff was estimated in the traditional way by rational method. But baseflow (underground feeding
The scientific heritage No 34 (2019) fraction of the rivers, or infiltration) was determined on the basis of the curve number methods' elements. The evaporation is one of the 3 main elements of water balance and is estimated by subtracting the sum of surface and underground flows from precipitation.
Thus, the synthesis of above 3 methods allows quickly and with small errors to determine:
1) The water resources and water balance elements of any territory and river catchment.
2) The amount of water consumed for infiltration and the fraction of underground feeding of rivers.
3) The amount of evaporation and potential evapotranspiration over any study area.
4) The assessment of the actual and maximal soil moisture.
5) The degree of influence of climatic and anthropogenic factors separately on changes in water balance, water resources and water losses.
6) Give a forecast of insurance against future natural risks with water-related and rational use of the water resources.
The volume of water resources and the runoff formation level of any area depends on 2 important factors — the humidity condition of territory (HCT) and the features of the surface area (LULC-Land-use & Land cover). The HCT- is the humidity level of a territory that determines the amount of water resources and runoff generation process. At present, when assessing
HCT and the runoff formation process, first of all, is preferred to determining of the maximum retention value (S) in the Western scientific literature [20,28,34,39].
The humidity coefficient (R) is determined with the ratio of precipitation to potential evapotranspiration. We have used at the assessment of the HCT with both sides of the evaluation criteria (S and R).
LULC (Land-use & Land cover)-is the general description of the surface area, or the sum of natural and human landscapes (vegetation cover, croplands, urban areas (settlements), bare soil and fallow lands, water bodies etc.).
The hydro-meteorological data are taken from statistical measurements of Ministry of Ecology and Natural Resources of the Azerbaijan Republic, data of ungauged area were obtained with GIS technology taking into account DEM features of gauged stations and interpolating of climate data. To determine the water balance in the first place using Rational method are found rational coefficients (surface runoff coefficients). LULC, HSG (hydrologic soil groups) and slope are the main factors of rational method. The discharge and volume of surface runoff are estimated on their basis. Table 1 lists rational runoff coefficients for various combinations of LULC, HSG and slope degrees by the main classifications [9,10,13,26,37].
Table 1
The rational runoff coefficients according to data of LULC, HSG and slope
LULC (Landuse and Land cover) Rational runoff coefficients, c
Slope degrees Slope degrees
< 2% 2-6% >6% < 2% 2-6% >6%
Soil group A Soil group B
Forest 0.08 0.11 0.14 0.10 0.14 0.18
Meadow 0.14 0.22 0.30 0.20 0.28 0.37
Pasture 0.15 0.25 0.37 0.23 0.34 0.45
Garden 0.11 0.16 0.21 0.16 0.19 0.27
Cropland (Cultivated land) 0.14 0.18 0.22 0.16 0.21 0.28
Industrial district 0.85 0.85 0.86 0.85 0.86 0.86
Commercial center 0.88 0.88 0.89 0.89 0.89 0.89
Street 0.76 0.77 0.79 0.80 0.82 0.84
Running water bodies 1.00 1.00 1.00 1.00 1.00 1.00
Non-stream water bodies 0.00 0.00 0.00 0.00 0.00 0.00
Residential areas 1/3 acre (rural) 0.28 0.32 0.35 0.30 0.35 0.39
Residential areas 1/8 acre (urban) 0.33 0.37 0.40 0.35 0.39 0.44
Unimproved and bare areas 0.65 0.67 0.69 0.66 0.68 0.70
Soil group C Soil group D
Forest 0.12 0.16 0.20 0.15 0.20 0.25
Meadow 0.26 0.35 0.44 0.30 0.40 0.50
Pasture 0.30 0.42 0.52 0.37 0.50 0.62
Garden 0.19 0.23 0.30 0.22 0.27 0.38
Cropland (Cultivated areas) 0.20 0.25 0.34 0.24 0.29 0.41
Industrial district 0.86 0.86 0.87 0.86 0.86 0.88
Commercial center 0.89 0.89 0.90 0.89 0.89 0.90
Street 0.84 0.85 0.89 0.89 0.91 0.95
Running water bodies 1.00 1.00 1.00 1.00 1.00 1.00
Non-stream water bodies 0.00 0.00 0.00 0.00 0.00 0.00
Residential areas 1/3 acre (rural) 0.33 0.38 0.45 0.36 0.40 0.50
Residential areas 1/8 acre (urban) 0.38 0.42 0.49 0.41 0.45 0.54
Unimproved and bare areas 0.68 0.70 0.72 0.69 0.72 0.75
The analysis of LULC data is carried out by satellite image of the selected periods. When developing digital images of LULC 2016, a satellite image (Landsat 8 (Enhanced Thematic Mapper (ETM +)) of the given territory was used, and separate types of LULC area were divided into sub-areas (polygons) by a mul-tispectral analysis. However, due to the lack of space images in 1963, detailed topographic maps and land-use plans of the territory were used. The classification of LULC types was justified by the US National Land Cover Database (NLCD-2011) [24].
Surface runoff determined by the Rational method is considered more reliable in comparison by other methods. In the Curve number method, preference is given to the permeability and soil moisture features of the territory. This method is more reliable in determining the fraction of infiltration in the water balance. However, to this day, the features of these methods have not been taken into account in the aggregate by one method.
Using the Rational method in determining surface runoff, and the Curve number method in the definition of infiltration and evaporation, we have reached the water balance values in the presence, or absence of observational data. The actual soil humidity (F) and the maximum retention (S) in concrete physical and geographical conditions of the territory reflect the degree of their infiltration capacity. Therefore, to determine
the share of underground feeding of rivers (or infiltration into the territory), we proposed the following semi-empirical equation as [46]:
F
U= ( L x i ).
v s'
In order to test the results we have used the obtained data of surface runoff coefficients with investigation over 29 river basins of the southern slope of the Greater Caucasus based on rational method and GIS technologies. The comparison of actual runoff data with data obtained using a rational method and GIS show that the error percentage ratios of 22 rivers from 29 has been under ±10%, only 7 rivers around ±10-15%. For example, the estimation of water resources and balance elements for chose territory is shown below.
The study area
The region is located in the Azerbaijan Republic, in the western side of the southern slope of the Greater Caucasus (figures 1 and 2 ). The center of the territory corresponds to 41°17'30" northern latitude and 46°58'30'' east longitude. The area is mostly lowland, with an area of 14.52 km2, an average height of 327.5 m, precipitation of 805 mm, temperature of 14.2°C, and a humidity coefficient of 0.88. The natural landscapes represented by forests and shrubs have remained at the level of 11.97%. A significant part of the territory (88.03%) is anthropogenic landscape.
LOCATION OF INVESTIGATED TERRITORY
Figure 1. View of location of the investigated territory on Republic of Azerbaijan
Figure 2. Satellite image of the investigated territory (2016)
The water balance elements and water resources of the study territory for 1963 (current-investigation) and 2016 (previous-investigation) years were estimated and for 2050 (forthcoming-investigation) was predicted in the presented research paper. When forecasting with climatic factors, the influence of anthropogenic (LULC) impacts were taken into account at the first time and were used the most popular climate change models (GCMs) such as GISS, GFDL-3, HadCM3, CCCM, UKMO, ECHAM5, etc. [7,8,19,30,33,35,51].
The fulfillment sequence of investigation
The investigation was carried out in sequence: 1) Were determined the main indicators at assessment of rational (surface) runoff coefficient — LULC, HSG (hydrological soil groups) and DEM (slope degree). In accordance with the differences in each of these indicators and using GIS technology the
sub-divisions are allocated on the territory. LULC data are defined by the satellite multispectral image of territory (it's possible "Landscapes", "Land-use" and topographic maps) [22].
HSG (hydrological soil groups) are determined by their granular composition. Respectively, with increasing surface runoff potential, they are divided into 4 groups (A, B, C, D). In determining HSG, they were based on classifications by the size of the fraction of soils mechanical texture [38,45,50].
By creating up a digital elevation model (DEM), the slope of the river basin was determined and according to the accepted method, it was calculated in three percent grades (<2%, 2-6%, >6%).
Figure 2 shows LULC (Land-use & Land cover) characteristics of the study territory for 1963 and 2016.
Figure 2. LULC data of the investigation area for 1963 and 2016.
2) Based on the LULC, HSG and slope of each sub-division, the shares of the rational runoff coefficient (c) for the subareas and an average value was obtained for the whole territory.
3) By the equation Qs=kxciA estimates the surface runoff of territory.
4) For estimation the underground feeding of the river (or infiltration of territory) we proposed a semi-
p
empirical formula as U = ( L x - ) [28,43,46].
Where, L — hydrological abstract, defined as L=
P-Qs.
5) Total runoff discharge is estimated the sum of surface and underground runoff:
Qt = Qs + U
The surface runoff and its underground feeding fraction represent both the income of the water balance
LULC changes covering the years 1963-
of the territory from fallen precipitation, but other elements (initial abstraction, actual soil moisture, evapotranspiration, etc.) as water losses. Therefore, the water resources are considered as the sum of surface runoff and baseflow.
6) By the equation W = Qt x 31.5 x 106 were assessed the water resources (W).
7) When predicting the dynamics of LULC changes in the period until 2050 the average annual statistical data changes and research reports of the world's scientific sources were taken as a basis. But when forecasting changes of meteorogical values (precipitation and temperature), popular general circulation climate models (GCMs) scenarios were used.
The obtained results The table 2 shows the LULC change rates in the covering the years 1963-2016 and 2016-2050.
Table 2
■2016 and 2016-2050 (by study area, in %)
LULC 1963 2016 2050 Annual avarage change, %
1963-2016 2005-2015
Residental (1/3 acre) 3.79 19.42 25.61 + 0.2894 + 0.1822
Cultivated areas 27.36 39.76 36.42 + 0.2296 - 0.0983
Pastures 7.58 10.55 14.68 + 0.0550 + 0.1214
Lake 0.29 0.19 0.19 - 0.0019 0.0000
Forests 37.02 11.97 12.02 - 0.4639 + 0.0014
Gardens 23.96 18.11 11.08 - 0.1083 - 0.2067
Total 100.0 100.0 100.0 0.0000 0.0000
The main meteorogical and humidity components of the territory were determined for 1963 and 2016 years on the background of actual atmospheric precipitation and temperature data, and the forecast values for year of 2050 by their expected data were found on the basis of different climate change models (GCMs) (table 3).
Table 3
Main meteorological and humidity components of the study area
Years Data sources and climate models P, mm t°, C° R F, mm S, mm
1963 factual 760 13.5 0.9139 365.6 1034.0
2016 factual 805 14.2 0.9598 383.3 955.6
2050 CCCM 749 15.8 0.8414 344.4 849.7
2050 G1SS 773 15.5 0.8826 357.2 876.9
2050 HadCM3 802 15.4 0.9259 373.3 909.8
2050 GFDL-3 813 14.8 0.9563 383.0 922.4
2050 ECHAM5 840 15.1 0.9868 395.7 952.9
2050 UKMO 786 15.7 0.8959 370.3 892.7
The calculated water resources and water balance elements in 1963, 2016 and 2050 for various climate change models are shown in the table 4. (Qs-surface runoff, U-baseflow, Qt-total runoff, E-actual evaporation, W-water resources).
Table 4
Water resources and water balance elements of the investigated area
Years Forecast sources Qs mm U mm Qt mm E mm W 106 m3
1963 factual 192.8 200.6 393.4 366.6 5.6479
2016 factual 240.1 226.6 466.7 338.3 6.7001
2050 CCCM 234.7 208.4 443.1 305.9 6.3598
2050 G1SS 242.2 216.2 458.4 314.6 6.5804
2050 HadCM3 251.3 225.9 477.2 324.8 6.8512
2050 GFDL-3 254.7 231.8 486.5 326.5 6.9836
2050 ECHAM5 263.2 239.5 502.7 337.3 7.2165
2050 UKMO 246.3 223.8 470.1 315.9 6.7550
The obtained data made it possible to estimate the influence of anthropogenic and climatic factors separately. Indirectly, the research is fulfilled only when studying the LULC data. That is, the assessment may be performed with unchanging-the same climatic factors for the previous year and in the LULC changes for the current year. In this case, the differences of values between the previous year and current year show only the impact of LULC components. But the direct way simultaneously are studied the role of both factors (climate and human activity) for the compared years.
The table of 5 reflects the percentage of influence of climatic and anthropogenic changes on water resources and the risks of their losses for the year 2050. The anthropogenic (human activities) changes are estimated in a predictable case only.
Table 5
Determination of the impact rate of climate and anthropogenic factors in forecasting
Years Forecast sources Rational surface coefficients, c Water resources, 106 m3 Water resources change, %
Total Climatic Human
1963 gauged 0.2537 5.6479 — — —
2016 gauged 0.2982 6.7001 +16.25 +6.68 +9.57
2050 CCCM 0.3133 6.3598 -5.35 -10.41 +5.06
2050 G1SS 0.3133 6.5804 -1.82 -6.88 +5.06
2050 HadCM3 0.3133 6.8512 +2.26 -2.80 +5.06
2050 GFDL-3 0.3133 6.9836 +4.23 -0.83 +5.06
2050 ECHAM5 0.3133 7.2165 +7.71 +2.65 +5.06
2050 UKMO 0.3133 6.7550 +0.82 -4.24 +5.06
As can be seen from table 3, the water resources of the territory were estimated 5.65 mln.m3 for 1963 and 6.70 mln.m3 in 2016. The predicted water resources for the year 2050 due to different climate forecast scenarios and LULC changes are also defined (mln.m3): 6.36-CCCM model, 6.58-GiSS, 6.85-HadCM3, 6.98-GFDL-3, 7.22-ECHAM5 and 6.76-UKMO. The study territory is located on the southern slope of the Greater Caucasus which manifests itself with unique consequences of climate change in recent years (that is, both precipitation and temperature increase). Therefore, the area showed itself in a very sensitive reaction when predicting the various climate change models.
In comparison with the background rate of 1963 year, the water resources of the territory in 2016 year increased +16.25% and this is related to +9.57% with anthropogenic impacts and +6.68% with climatic changes. As can be seen from the table above, if the forecasts were fulfilled only by climatic data, then there would be serious errors in the estimation of the water balance elements. So, under changes of anthropogenic (LULC) impacts on the surface runoff has continueusly increased. The rational (surface) coefficients reflect precisely the influence of human activities changes and and most of these changes (urbanization, bare soil, fallow, pastures etc.), in general, play a positive role.. The rational runoff coefficient in 1963 amounted to 0.2537; in 2016 year 0.2982 and forecasted to 2050 year 0.3133. If climatic factors were not taken into account, then water resources for 2016 with a comparison of 1963 would increase + 9.57% only due to human changes. But due to climatic factors (especially precipitation increase), the water resources also increased by + 6.68%, and were + 16.25% in together. In 2050, only under anthropogenic impacts (c=0.3133), water resources should be increased by 5.06% compared to 2016. And taking into account the different models of climate change in the forecast for 2050, the volume of water resources increased and decreased compared to 2016. Thus only in the research territory, due to changes of 2 climatic (precipitation and temperature) and 6 anthropogenic (settlements, croplands, pastures, water bodies, gardens, forests) factors it possible to assessed water resources in 632,880 scenarios using GIS technology. This again proves the advantages of our proposed methodology.
All results are obtained by processing of complex runoff-forming factors applying special comparison and computing programs using GIS technology, there are high accuracy and their application are possible in solution the major water-related issues.
Conculusion At present, there is no such sector of the economy, the development of which is possible without the availability of sufficient water resources. The main territory of the Azerbaijan Republic is situated within arid climate and vast majority of water resources are involved economic production. The total water resources of Azerbaijan is estimated at 30.9 km3. However, most of these resources enter the territory of the Republic in transit and their value (20.6 km3) depends entirely on the level of their use in neighboring countries. 10.3 km3 are local water resources, and they do not satisfy all the demands of the national economy (1214 km3). Another problem related to water is the change in climatic conditions and the activation in recent years of changes in other natural-anthropogenic factors. The provision of safe and sufficient supplies of water already a problem in many areas of Republic, and as population increase, economy development it is problem that will continue to escalate. In states with a current 30%, as was estimated, more than 40% in the near future deficit of general water resources. This situation is complicated by the climate change, intensive human impact on the environment. Therefore, analysis of the role of the climatic and antropogenic factors can be helpful to identify a range of alternative water management scenarios. The results of estimation of water resources loss will help to develop priority
adaptation measures to minimize the consequences ot the water crisis. Spatio-temporal changes occurring in the water resources and the proportions of individual components in the water balance require their continuous study and put on the forefront the exploration and application of more modern, operational and more sensitive to changes in methods. The combined methodology proposed by us is operational and enables to calculate the water balance elements, water resources and their loss risks in spatio-temporal changes of climatic and human activities factors. The coefficients obtained by the rational method reflect the degree of precipitation formation into the surface runoff and makes it possible to determine its value in any areas. An equation for the determination of base-flow also permit to estimate and with sufficient accuracy the total river runoff and water resources of any territory. The study reveals that the new model offered by us can be used to estimate water resources any situation and when adequate hydrological information is not available.
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