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Hydroclimatic changes and drivers in the Sava River Catchment and comparison with Swedish catchments.

Levi L, Jaramillo F, Andričević R, Destouni G - Ambio (2015)

Bottom Line: In a hydropower dominated part of the SRC, unlike in an unregulated part, we find increase in average annual evapotranspiration and decrease in temporal runoff variability, which are not readily explainable by observed concurrent climate change in temperature and precipitation and may be more related to landscape-internal change drivers.Among the latter investigated here, results indicate hydropower developments as most closely related to the found hydroclimatic shifts, consistent with previous such indications in studies of Swedish hydropower catchments.Overall, the present results have quantitatively framed the recent history and present state of hydroclimate in the SRC, of relevance for water resources in several countries and for a majority of their populations.

View Article: PubMed Central - PubMed

Affiliation: Department of Sustainable Development, Environmental Science and Engineering (SEED), Royal Institute of Technology (KTH), Teknikringen 76, 100 44, Stockholm, Sweden. llevi@kth.se.

ABSTRACT
In this study, we investigate long-term hydroclimatic changes and their possible relation to regional changes in climate, land-use and water-use over the twentieth century in the transboundary Sava River Catchment (SRC) in South Eastern Europe. In a hydropower dominated part of the SRC, unlike in an unregulated part, we find increase in average annual evapotranspiration and decrease in temporal runoff variability, which are not readily explainable by observed concurrent climate change in temperature and precipitation and may be more related to landscape-internal change drivers. Among the latter investigated here, results indicate hydropower developments as most closely related to the found hydroclimatic shifts, consistent with previous such indications in studies of Swedish hydropower catchments. Overall, the present results have quantitatively framed the recent history and present state of hydroclimate in the SRC, of relevance for water resources in several countries and for a majority of their populations. This provides a useful basis for further assessment of possible future hydroclimatic changes, under different scenarios of climate change and land/water-use developments in the region.

No MeSH data available.


Change (Δ) in hydroclimatic variables and hydropower production development in the SRC and its subcatchments. a Temperature (T), precipitation (P), runoff (R). b Relative actual evapotranspiration (AETwb/P), coefficient of variation of monthly runoff CV(R) and developed hydropower production per catchment area (HP). Error bars show 95 % confidence intervals for the hydroclimatic and hydropower changes
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Fig5: Change (Δ) in hydroclimatic variables and hydropower production development in the SRC and its subcatchments. a Temperature (T), precipitation (P), runoff (R). b Relative actual evapotranspiration (AETwb/P), coefficient of variation of monthly runoff CV(R) and developed hydropower production per catchment area (HP). Error bars show 95 % confidence intervals for the hydroclimatic and hydropower changes

Mentions: By the end of the year 1993, 16 times more hydropower production per catchment area (Figs. 4a, b), 13 times more water surface area of man-made reservoirs, and 50 times more water volume were developed in the Kozluk catchment than in the Slavonski Brod catchment. Figure 5a and b summarizes the changes in average T, P, R, AETwb/P, CV(R), and hydropower production (HP) values from 1931–1960 to 1964–1993, with 95 % confidence interval bars as obtained from the two-tailed paired Student t test for the three catchments. The purely atmospheric climate changes ΔT and ΔP (Fig. 5a) are not statistically significant for any of the catchments (at 0.05 significance level). However, the decrease in runoff variability ΔCV(R) is significant (at 0.05 significance level) only in the Kozluk catchment with the greatest hydropower production per catchment area. In the whole SRC with 4 times lower hydropower production per catchment area (Fig. 5b) and the Slavonski Brod catchment, with 16 times lower hydropower production per catchment area than in the Kozluk catchment, there is no significant change in ΔCV(R) (Fig. 5b). For all three catchments, we also performed an ANCOVA test under 0.05 significance level in order to further check the influence of the hydropower production proxy (as an independent variable) on AETwb/P (as an outcome variable), taking into consideration AETBclim/P and AETTclim/P (as covariant variables). The test showed highly significant (P < 0.001) change in slope of 20-year running average (1940–1983) of AETwb/P for Kozluk catchment when taking into consideration the influence of hydropower, and no significant change when taking into consideration only climate change. No such significant results were found for Slavonski Brod and the SRC catchments. Figure 6 finally shows a direct comparison between SRC and Swedish (Destouni et al. 2013) catchment results with regard to changes in AETwb/P (Fig. 6a) and CV(R) (Fig. 6b) versus change in developed hydropower production per catchment area. For the Swedish catchments, there is positive correlation for AETwb/P (R2 = 0.27, Fig. 6a) and particularly so for CV(R) (R2 = 0.83, Fig. 6b). When including the SRC results for the two distinctly different subcatchments Slavonski Brod and Kozluk and removing local noise from the data by considering average results for catchments with hydropower production that is greater (blue square; for 4 such catchments cross-regionally) and smaller (yellow rectangle; for 7 such catchments cross-regionally) than 100 MWh km−2, the resulting two average data points fit well to the regression lines for individual catchment data. Figure 6 also shows predicted values for the SRC catchments, calculated on the basis of the Swedish catchment results.Fig. 5


Hydroclimatic changes and drivers in the Sava River Catchment and comparison with Swedish catchments.

Levi L, Jaramillo F, Andričević R, Destouni G - Ambio (2015)

Change (Δ) in hydroclimatic variables and hydropower production development in the SRC and its subcatchments. a Temperature (T), precipitation (P), runoff (R). b Relative actual evapotranspiration (AETwb/P), coefficient of variation of monthly runoff CV(R) and developed hydropower production per catchment area (HP). Error bars show 95 % confidence intervals for the hydroclimatic and hydropower changes
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Related In: Results  -  Collection

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Fig5: Change (Δ) in hydroclimatic variables and hydropower production development in the SRC and its subcatchments. a Temperature (T), precipitation (P), runoff (R). b Relative actual evapotranspiration (AETwb/P), coefficient of variation of monthly runoff CV(R) and developed hydropower production per catchment area (HP). Error bars show 95 % confidence intervals for the hydroclimatic and hydropower changes
Mentions: By the end of the year 1993, 16 times more hydropower production per catchment area (Figs. 4a, b), 13 times more water surface area of man-made reservoirs, and 50 times more water volume were developed in the Kozluk catchment than in the Slavonski Brod catchment. Figure 5a and b summarizes the changes in average T, P, R, AETwb/P, CV(R), and hydropower production (HP) values from 1931–1960 to 1964–1993, with 95 % confidence interval bars as obtained from the two-tailed paired Student t test for the three catchments. The purely atmospheric climate changes ΔT and ΔP (Fig. 5a) are not statistically significant for any of the catchments (at 0.05 significance level). However, the decrease in runoff variability ΔCV(R) is significant (at 0.05 significance level) only in the Kozluk catchment with the greatest hydropower production per catchment area. In the whole SRC with 4 times lower hydropower production per catchment area (Fig. 5b) and the Slavonski Brod catchment, with 16 times lower hydropower production per catchment area than in the Kozluk catchment, there is no significant change in ΔCV(R) (Fig. 5b). For all three catchments, we also performed an ANCOVA test under 0.05 significance level in order to further check the influence of the hydropower production proxy (as an independent variable) on AETwb/P (as an outcome variable), taking into consideration AETBclim/P and AETTclim/P (as covariant variables). The test showed highly significant (P < 0.001) change in slope of 20-year running average (1940–1983) of AETwb/P for Kozluk catchment when taking into consideration the influence of hydropower, and no significant change when taking into consideration only climate change. No such significant results were found for Slavonski Brod and the SRC catchments. Figure 6 finally shows a direct comparison between SRC and Swedish (Destouni et al. 2013) catchment results with regard to changes in AETwb/P (Fig. 6a) and CV(R) (Fig. 6b) versus change in developed hydropower production per catchment area. For the Swedish catchments, there is positive correlation for AETwb/P (R2 = 0.27, Fig. 6a) and particularly so for CV(R) (R2 = 0.83, Fig. 6b). When including the SRC results for the two distinctly different subcatchments Slavonski Brod and Kozluk and removing local noise from the data by considering average results for catchments with hydropower production that is greater (blue square; for 4 such catchments cross-regionally) and smaller (yellow rectangle; for 7 such catchments cross-regionally) than 100 MWh km−2, the resulting two average data points fit well to the regression lines for individual catchment data. Figure 6 also shows predicted values for the SRC catchments, calculated on the basis of the Swedish catchment results.Fig. 5

Bottom Line: In a hydropower dominated part of the SRC, unlike in an unregulated part, we find increase in average annual evapotranspiration and decrease in temporal runoff variability, which are not readily explainable by observed concurrent climate change in temperature and precipitation and may be more related to landscape-internal change drivers.Among the latter investigated here, results indicate hydropower developments as most closely related to the found hydroclimatic shifts, consistent with previous such indications in studies of Swedish hydropower catchments.Overall, the present results have quantitatively framed the recent history and present state of hydroclimate in the SRC, of relevance for water resources in several countries and for a majority of their populations.

View Article: PubMed Central - PubMed

Affiliation: Department of Sustainable Development, Environmental Science and Engineering (SEED), Royal Institute of Technology (KTH), Teknikringen 76, 100 44, Stockholm, Sweden. llevi@kth.se.

ABSTRACT
In this study, we investigate long-term hydroclimatic changes and their possible relation to regional changes in climate, land-use and water-use over the twentieth century in the transboundary Sava River Catchment (SRC) in South Eastern Europe. In a hydropower dominated part of the SRC, unlike in an unregulated part, we find increase in average annual evapotranspiration and decrease in temporal runoff variability, which are not readily explainable by observed concurrent climate change in temperature and precipitation and may be more related to landscape-internal change drivers. Among the latter investigated here, results indicate hydropower developments as most closely related to the found hydroclimatic shifts, consistent with previous such indications in studies of Swedish hydropower catchments. Overall, the present results have quantitatively framed the recent history and present state of hydroclimate in the SRC, of relevance for water resources in several countries and for a majority of their populations. This provides a useful basis for further assessment of possible future hydroclimatic changes, under different scenarios of climate change and land/water-use developments in the region.

No MeSH data available.