3 test sites: 1.belgrade gw source 2. pek river catchment 3. nisava river catchment-mediana site

- Climate Change and Impacts on Water SupplyCC-WaterS

Title


Title

3 test sites: 1.Belgrade GW Source2. Pek River

Catchment3. Nisava River

Catchment-Mediana site


Title

Main characteristics of the Belgrade test area • Test Area 18 includes 241 km2 of lowland of the Sava Valley.• There is one groundwater body of intergranular porosity.• It is largely recharged by the Sava River and discharged via

the wells of the Belgrade Groundwater Source (4-5 m3/s).

Nominated Natura 2000 sites

Proposed Natura 2000 sites

Map showing groundwater level contours in October 2008


Title

Methodology, simplifications and assumptions • The elements of the water balance were integrated by

hydrodynamic calculations using MODFLOW 2000 software• Main simplifications and assumptions• River Sava -studied aquifer contact will retain const.

(conductance of the river bottom is constant)• The boundary condition in the disregarded portion of the

area is predominantly under the influence of vertical water balance parameters -climate parametars

• The current status of the proposed Natura 2000 sites is a result of the groundwater regime (the impact of irrigation/drainage canals is small or negligible).


Title

Reference value for 1961-90• Model calibration, validation and sensitive analisys – done for the 2005-2008

with needed opservations – data for river water fluctation, water abstraction, ground water level fluctation, temperature, precipitation, evapotranspiration GW recharge,

• Reference status of the GWB – GW levels at selected sites (ecological criteria) in 2008 year.

Future – estimated value• Selection of representative periods - Long-term (8 to 10 years) average amounts

of precipitation – MINIMUM• As a result, the 2021-29 period was deemed to reflect the representative state

for 21-50 period, and the 2093-2100 period to reflect the average state for 71-100.

• GW calculations -Hydrodynamic analyses using modified boundary conditions derived on the basis of precipitation and temperature in future periods.


Title• Empirical functions were used for the correlation between precipitation and “potential” infiltration by month.

The rate of evaporation from grassland at ground level was computed applying a modified Penman method. Effective infiltration was computed using the hydrodynamic model, as the difference between a given potential infiltration rate and the computed rate of evaporation from the water table, as a function of the depth-to-groundwater.

• Based on the correlation between PET and temperature levels by month, it was assumed that the current correlation can be used to predict future potential evapotranspiration. According to these data, the effect of temperature on PET is more pronounced between May and October (fig.1a).

• For future estimation of the ETo at critical periods, the “registered” historical value was selected. Based od the average annual temperature and average summer temperatures in future periods, and the closest recorded (with all data needed) values, ET0 in the prognostic calculations was adopted. Specifically, 1994 is the representative year for the 2021-2050 period, and 2000 is the representative year for the 2071-2100 period.

Correlation between recorded temperatures and PETo-Penman (Fig 1a) and correlation between precipitation and infiltration by month (fig 1.b)

Po

ten

tial i

nfil

tra

tion

(m

m/m

on

th)

Precipitation (mm/month)


TitleMethodology, simplifications and assumptions ... Continue

Assessment of groundwater levels, river fluctuations, abstractions, drainage system performance and climate data, and selection of periods for further analysis

Monthly precipitation levels ---> infiltration, temperature and

evapotranspiration

Assessment of dependency of boundary conditions on met. data

Calibration of the H-D model parameter

Method Empirical approach, Penman Statistical approach,

correlation MODFLOW 2000 1960-2006 1982-1990 2005-2009

Calculations - H-D model - MODFLOW 2000,

by month

Present, 2008 2021-2050 2071-2100 Remarks

Sava River Synthetic year 85-2009 data

Synthetic year 85-2009 data k/d same as today

User demand 2005-2009 rate of abstraction

from 4500 to 4000 l/s

Planned groundwater source revitalization – most important user

Same as in the previous period

Change from 4000 to 5100 l/s, agricultural demand only 70 l/s in

2100 Temperature Average for the period Average for the period

Precipitation Belgrade, 2005-2009 Average and for the critical

2021-2029 period Average and for the

critical 2093-2100 period

Infiltration Empirical dependency on

precipitation Empirical approach, 2021-

2029 Empirical approach,

2093-2100

Potential Eto Grassland, Penman, Belgrade

2005-2009

Based on average and summer temperatures,

selected year 1994

Based on average and summer temperatures,

selected year 2000

Available water resources

Present, 2008 Future, 2021-50 Future, 2071-2100

Criteria

Present groundwater levels and discharge from the

Zivaca Pond Present GWL and Q

from the Zivaca Pond Present GWL and Q

from the Zivaca Pond

Constraints Reduction in abstractions for drinking water supply

Reduction in abstractions for drinking

water supply

Additional water management measures

needed


TitleTitle

Water demand of the ecosystems

The ecosystem demand is associated with the need to maintain favorable groundwater levels in the forest zones (Bojčinska Šuma and Crni Gaj), and to conserve the groundwater regime which affects the extent of water losses due to infiltration from the Živača Pond.

The extent to which these conditions may vary due to climate change is shown via duration curves for reference parameters, water levels for the forests and the rate of infiltration for the Živača Pond. Graphics were prepared for the year 2008, which is representative of a sustainable state, and the average, synthetic year which represents the 2021-50 period, and finally the 2071-2100 period.


TitleResultsWith regard to the analyzed aquifer (or water resource), no variation in

water availability for drinking water supply is expected in view of the configuration of the water source and the size of the river from which the aquifer is predominantly recharged.

However, an analysis of the potential impact of climate scenarios on the forested areas classified as Natura 2000 sites, shows a different picture. Based on graphically interpreted groundwater levels at these sites, a significant impact may be expected in the Bojčinska Šuma area, which is at a relatively large distance from the Sava River and the wells of the Belgrade Groundwater Source.

Computed water level duration curves for Crni Lug and Bojnička Šuma (2008 state and two future states - 2021-2050 and 2071-2100).

Duration (%)

GW

leve

ls (

a.s

.l.)

Duration (%)

GW

leve

ls (

a.s

.l.)


Title

Main characteristics of the artificial recharged source “Mediana” test area -the Nisava river catchment

The size of the Nisava river catchment area is 4,086 km2, of which 1,096 km2 is in Bulgaria (transboundary river)

Maximum capacity -600 l/s


Title Sensitivity to Climate Change (observed indicators)

Floods: On 27 November 2007, the Nišava flooded farmland in the Village of Dolac, at the entrance to the Sićevo Gorge (Serbia Waters, 2007).

Droughts: Spatial distribution of drought in 1990(a) and 2000(b), and severity expressed in terms of SPI. (Spasov et al.)


TitleMethodology, simplifications and assumptions

- base line period 1961-1990, validation period 1991-2006 (real climate data from 8 stations) - Estimation of future monthly discharges for periods 2021-2050 and 2071-2100 (precipitation

and temperature given by BOKU University, corrected for higher altitude stations), - water balance elements: WATBAL model (1961-1990), MODFLOW (“Mediana” test site), for future evapotranspiration – Empirical equation (depending on T, P) – calibrated for 1961-1990 (Isailovic et al. 2010). - For estimation of average monthly discharges – future period (till 2100) is used Model VNC (developed in Institute Jaroslav Cerni) – non linear correlation model - outputs – GIS maps, data base (monthly discharges, P, T, Q min.sust., …)

Main simplifications and assumptions

• Mediana artificial recharged water source directly depending on the Nisava river discharges at profile of water intake

• Groundwater levels in Mediana test area are strongly dependent on water in infiltration lakes (feeding of that part of aquifer is stopped by permeable barrier and drainage system)

• Upstream multipurpose reservoir “Zavoj”, since the beginning of its operation has been used only for the production of electric power in the HPP “Zavoj” not for water supply and irrigation


Title

Elements for surface water balance

Average runoff in the Nišava river basin

Average annual temperatures in the Nišava River Basin

Humidity in the Nišava River Basin

Precipitation in the Nišava River Basin


Title

Multi-parameter non linear correlation model VNC

The model is based on the theory of non-linear standardized correlation

The essence of the VNC model is the establishment of linear correlations between standardized variables:

- Precipitation and temperature,independent variables

-dependent variable is the discharge at the hydrological cross-section (at intake for water supply source “Mediana” – Nis gaug.stat.

-The model boundaries were the actual boundaries of the river basin, and the exit cross-section was the Niš hydrological station located downstream from the Mediana water intake.


Title

1961-1990 2021-2050 2071-2100 Period

P av. T P T P T AVER 49.8 8.3 47.2 10.7 45.5 11.8

30.89 7.605 35.723 8.232 35.446 8.778 Cv 0.620 0.888 0.757 0.772 0.779 0.744 Cs 1.081 -0.147 2.053 -0.023 1.377 0.001

MAX 220.0 23.3 358.3 28.6 234.9 28.6 MIN 0.0 -8.5 0.0 -6.2 0.0 -5.0

Results from VNC Model

Average annual discharges of the Nišava River

Period 1961-1990 2021-2050 2071-2100 Qo Q Q Aver. 30.7 27.17 25.4 23.873 17.55 19.297 Cv 0.844 0.675 0.758 Cs 1.735 1.20 1.422 MAX 141 114 122 MIN 2.69 3.13 2.69

Average monthly precipitation and air temperature levels in the Nišava River Basin


Title

2021-2050 Nišava discharges at profile Niš

y = 0,0023x + 23,427

0102030405060708090

100110120

jan

.20

21

jan

.20

22

jan

.20

23

jan

.20

24

jan

.20

25

jan

.20

26

jan

.20

27

jan

.20

28

jan

.20

29

jan

.20

30

jan

.20

31

jan

.20

32

jan

.20

33

jan

.20

34

jan

.20

35

jan

.20

36

jan

.20

37

jan

.20

38

jan

.20

39

jan

.20

40

jan

.20

41

jan

.20

42

jan

.20

43

jan

.20

44

jan

.20

45

jan

.20

46

jan

.20

47

jan

.20

48

jan

.20

49

jan

.20

50

jan

.20

51

2071-2100 Nišava discharges at profile Niš

y = -0,0172x + 63,733

0102030405060708090

100110120130

jan.

2071

jan.

2072

jan.

2073

jan.

2074

jan.

2075

jan.

2076

jan.

2077

jan.

2078

jan.

2079

jan.

2080

jan.

2081

jan.

2082

jan.

2083

jan.

2084

jan.

2085

jan.

2086

jan.

2087

jan.

2088

jan.

2089

jan.

2090

jan.

2091

jan.

2092

jan.

2093

jan.

2094

jan.

2095

jan.

2096

jan.

2097

jan.

2098

jan.

2099

jan.

2100

2021-2050 and 2071-2100 Discharge forecasts for the Nišava River at Niš.


TitleAvailable water for artificial recharged water source “Mediana” – at profil Nis

(water intake)Criteria need to be fulfilled

• According to Serbian low, minimum sustainable flow must be provided downstream from a surface water intake, to ensure the survival and growth of downstream biocenoses and meet the water demand of downstream users (Official Gazette RS 30/10). The minimum 95% average monthly discharge is used to derive this flow rate.

min,95%maxQ Qmin,sust.flow

For future periods 2021-2050 and 2071-2100 available discharge at Niš profile is calculated on the proposed formula :

Qavailable = Q(time,p)_Nisava – Qmin.sus.flow_Nisava.


Title

Results:

-Qaverag.yearl. will decrease from 30.7 m3/s to 27.1 m3/s (the end of 2050.) as to 25.4 m3/s (in period 2071-2100).

-Approximately 20% of available surface water will be lost with present water needs and efficiency of Zavoj accumulation

-Critical periods for Mediana test area will be summer months (July-August) in period 2021-2050 which will be extended to September and October at the end of 2071-2100 period

- Extreme events (droughts and floods) could make significant impact on water supply system NIVOS for Nis water supply (decreasing of karst spring discharges make pressure to Mediana test site also as increasing turbidity after heavy rain)


TitleConclusions for “Mediana” test site:

• ‘’Zavoj’’ reservoir shuold provide the required amount of water for water supply, and that the amount of water discharged from the reservoir after its hydro energetic potential has been used – regulated flow in the Nisava, meets the irrigation water demands in the Nisava basin and significantly affects the small waters enrichment in the dry seasons.

• Ecological criteria must be satisfied downstream from water intake • Significant impact of Climate Changes on depending biodiversity may be expected

in upstream part of Nisava river basin where are protected areas : the Sićevačka Klisura (Sićevo Gorge) and the Jelašnička Klisura (Jelašnica Gorge) Special Nature Reserve.


Title

THANK YOU FOR YOUR ATTENTION

3 test sites: 1.belgrade gw source 2. pek river catchment 3. nisava river catchment-mediana site

Documents