physiographic conditions of the territory, the
characteristics of its water regime and the nature
of the use (Water Resources 2012).
The climate change and the increasing of
anthropogenous effect on the river runoff during
the last 20–30 years are observed. Hydrological
regime for the Neman River basin is determined
by the natural fluctuations of meteorological
elements and anthropogenic factors. In this case,
the role of the anthropogenic factors increases
every year despite the economic downturn, and
inadequate attention to these factors may lead to
significant errors in the determination of estimated parameters (Ikonnikov et al. 2003; Volchak and Kirvel 2013).
The aim of our research is the forecasting
changes in river runoff for the Neman River basin
using two scenarios of economic development
and climate change (A1B and B1).
Research performed under the UNDP project
00079039 “Management of the Neman River basin
with account of adaptation to climate change”.
3.2 Data Sources
The Neman River basin is shown in Fig. 3.1
(Korneev et al. 2014).
The data sources are based on the materials
for the 24 hydrological stations at the Neman
River in Belarus and Lithuania since 1961 till
2009 (Table 3.1).
The climatic information consisted of the air
temperature, precipitation and deficits of air
humidity since 1961 till 2010 for 23 meteorological stations were used (Table 3.2).
3.3 Research Methods
For the research purposes, Mezentsev’s method
of the hydrological-climatic calculations was
adapted. The method is based on joint solution of
the equations for water and thermal balances
(Mezentsev 1995). During the research, we
devised a multi-factor model that includes the
standard equation of water balance. The
developed model is used to assess the possible
changes in runoff according to the various
hypotheses of climate fluctuations and anthropogenic impacts on water resources.
The equation of water balance is following:
HðIÞ ¼ EðIÞ þ Y K ðIÞ Æ DWðIÞ;
ð1Þ
where H(I)—total humidity, mm; E(I)—total
evaporation, mm; Y K (I)—total calculated runoff,
mm; DW(I)—changes of humidity reserves of the
active soil layer, mm; I—interval of averaging.
The total evaporation is given by:
EðIÞ ¼ E m ðIÞ 1 þ
EmðIÞ
WHB þ VðIÞ
1ÀrðIÞ
KXðIÞ þ gðIÞ
WHB
þ VðIÞ
! nðIÞ
2
4
3
5
À
1
nðIÞ
; ð2Þ
where E m ðIÞ—maximum total evaporation, mm;
W HB —minimum humidity ratio of the soil, mm;
VðIÞ ¼ WðIÞ=W HB —relative index of the
humidity of soils at the beginning of calculating;
KX(I)—sum of precipitation, mm; g(I)—soil–
water balance component, mm; r(I)—parameter
depending on water physical properties and
mechanical composition of soils; n(I)—parameter depending on physical–geographical conditions of runoff.
Relative index of the soil humidity at the end
of calculation period is determined from the
following relations
VðI þ 1Þ ¼ VðIÞ Á
V av ðIÞ
VðIÞ
rðIÞ
;
ð3Þ
V av ðIÞ ¼
KXðIÞ þ gðIÞ
W HB
þ VðIÞ
E m ðIÞ
W HB
þ VðIÞ
1ÀrðIÞ
! 1
rðIÞ
:
ð4Þ
The values V av ðIÞ are compared with the relative index of the total humidity V TH . If V av ðIÞ
V TH then must be taken the calculated value of
the relative average humidity, otherwise, when
V av ðIÞ ! V TH then taken V av ðIÞ = V TH and the
value (V av ðIÞ-V TH )ÁW HB refers to surface runoff.
The maximum total evaporation is according
to the method described in Volchak (1986).
14
A. A. Volchak and S. Parfomuk
characteristics of its water regime and the nature
of the use (Water Resources 2012).
The climate change and the increasing of
anthropogenous effect on the river runoff during
the last 20–30 years are observed. Hydrological
regime for the Neman River basin is determined
by the natural fluctuations of meteorological
elements and anthropogenic factors. In this case,
the role of the anthropogenic factors increases
every year despite the economic downturn, and
inadequate attention to these factors may lead to
significant errors in the determination of estimated parameters (Ikonnikov et al. 2003; Volchak and Kirvel 2013).
The aim of our research is the forecasting
changes in river runoff for the Neman River basin
using two scenarios of economic development
and climate change (A1B and B1).
Research performed under the UNDP project
00079039 “Management of the Neman River basin
with account of adaptation to climate change”.
3.2 Data Sources
The Neman River basin is shown in Fig. 3.1
(Korneev et al. 2014).
The data sources are based on the materials
for the 24 hydrological stations at the Neman
River in Belarus and Lithuania since 1961 till
2009 (Table 3.1).
The climatic information consisted of the air
temperature, precipitation and deficits of air
humidity since 1961 till 2010 for 23 meteorological stations were used (Table 3.2).
3.3 Research Methods
For the research purposes, Mezentsev’s method
of the hydrological-climatic calculations was
adapted. The method is based on joint solution of
the equations for water and thermal balances
(Mezentsev 1995). During the research, we
devised a multi-factor model that includes the
standard equation of water balance. The
developed model is used to assess the possible
changes in runoff according to the various
hypotheses of climate fluctuations and anthropogenic impacts on water resources.
The equation of water balance is following:
HðIÞ ¼ EðIÞ þ Y K ðIÞ Æ DWðIÞ;
ð1Þ
where H(I)—total humidity, mm; E(I)—total
evaporation, mm; Y K (I)—total calculated runoff,
mm; DW(I)—changes of humidity reserves of the
active soil layer, mm; I—interval of averaging.
The total evaporation is given by:
EðIÞ ¼ E m ðIÞ 1 þ
EmðIÞ
WHB þ VðIÞ
1ÀrðIÞ
KXðIÞ þ gðIÞ
WHB
þ VðIÞ
! nðIÞ
2
4
3
5
À
1
nðIÞ
; ð2Þ
where E m ðIÞ—maximum total evaporation, mm;
W HB —minimum humidity ratio of the soil, mm;
VðIÞ ¼ WðIÞ=W HB —relative index of the
humidity of soils at the beginning of calculating;
KX(I)—sum of precipitation, mm; g(I)—soil–
water balance component, mm; r(I)—parameter
depending on water physical properties and
mechanical composition of soils; n(I)—parameter depending on physical–geographical conditions of runoff.
Relative index of the soil humidity at the end
of calculation period is determined from the
following relations
VðI þ 1Þ ¼ VðIÞ Á
V av ðIÞ
VðIÞ
rðIÞ
;
ð3Þ
V av ðIÞ ¼
KXðIÞ þ gðIÞ
W HB
þ VðIÞ
E m ðIÞ
W HB
þ VðIÞ
1ÀrðIÞ
! 1
rðIÞ
:
ð4Þ
The values V av ðIÞ are compared with the relative index of the total humidity V TH . If V av ðIÞ
V TH then must be taken the calculated value of
the relative average humidity, otherwise, when
V av ðIÞ ! V TH then taken V av ðIÞ = V TH and the
value (V av ðIÞ-V TH )ÁW HB refers to surface runoff.
The maximum total evaporation is according
to the method described in Volchak (1986).
14
A. A. Volchak and S. Parfomuk