**3.2 Effects of climate change on related activities**

### *3.2.1 Sinú-Caribe basin*

The influence of climate change in this area of the country was analyzed, evaluating the supply-demand relationship. The activities related to hydroelectric power were taken into account in four investigations that will be briefly described in this section.

This area of the country is deserted due to the anthropic activity in the riverbed of the basin, in addition to the deforestation associated with different activities. It is a region of great importance for the country considering that approximately 66% of the electricity in Colombia is generated in hydroelectric plants [15] and that 3.7% of that value is a direct contribution of the Urra I system, located in the Sinú-Caribe basin. Moreover, it is susceptible to flooding; so the occurrence of extreme precipitation events is important for research related to climate change, considering that due to its influence the events will tend to be more frequent in the future [3].

A model was made using WEAP 2.1 software, to simulate hydrological processes in the scenarios concerning anthropogenic changes, land use, demands, and regulations among others. Its methodology is based on obtaining information on the daily consumption and activities in the study area, and their corresponding future increases based on projections. Then, it was contrasted with the reduction in supply due to environmental flow and quality considerations, as well as the possible variation in both temperature and precipitation and its consequent influence on the change in supply. Using WEAP, aspects of the supply-demand relationship were determined, such as unsatisfied demand, demand coverage, supply requirement, supply delivered, demand increase, and resource pressure indices. All scenarios are considered to be consistent with an increase in temperature and a positive or negative change in precipitation, as shown in Appendix 1, with a consequent

**Model/variable Electricity generation Flow**

*Effects of Climate Change on Water Resources, Indices, and Related Activities in Colombia*

CCSRNIES\_A21 0.7 16.5 5.9 CSIROMK2B\_A21 11.3 25.4 2.3 CGCM2\_A21 0.8 16.5 11.8 CGCM2\_A22 13.7 27.4 13.3 CGCM2\_A23 13.4 27.1 11.3 HadCM3\_A21 35.2 45.5 34.9 HadCM3\_A22 25.9 37.7 23.8 HadCM3\_A23 2.9 18.3 14.2 HadCM3\_A2\_SDSM 0.6 15.4 2.3

Statistic 27.2 38.8

*Changes in hydroelectric power generation and its related variables [7].*

*Reference scenario or baseline (1418.9 GWh/year).*

*Maximum generation capacity (1687.2 GWh/year).*

*DOI: http://dx.doi.org/10.5772/intechopen.90652*

**Change %1 Change %<sup>2</sup> Change %**

As a result, it was concluded that in all scenarios it is not possible to supply the demand for water resources in all sectors and activities (commercial, industrial, rural, and urban areas), leading to a progressive growth of unsatisfied demand for

From this research, it is important to highlight the allocation of weights to

corresponding increase and decrease in temperature and precipitation respectively. Accordingly, a single weighted average scenario was proposed, where the worst possible scenarios are given a greater weight. Therefore, this scenario becomes a tool for planning water conservation strategies, such as the implementation of technologies for the reuse or efficient use of water, as well as the inclusion of

It was concluded that the proposed methodology and application of the WEAP tool allow to have a broader view of the resource in a region, allowing a better management of the water resource, with the possibility of planning strategies properly and taking into account adverse effects. This establishes the need to carry out a regionalization of climate change in order to develop tools that allow a detailed observation of its impact at local level. Finally, the inclusion of hydrological variables allows planning based on the water supply, reducing uncertainty in some way.

climate change models based on their contribution to the flow, and their

decrease in the water flow or supply available.

the year 2039, as shown in **Figure 2**.

vegetation conservation.

**79**

*1*

*2*

**Table 5.**

For the first investigation carried out in 2009 [7], the precipitation and temperature data were initially obtained for two weather stations in the area. Then, some statistical regressions were performed to establish the relationship between the mentioned variables and the flow measured in the basin. Regarding the future projection of precipitation and temperature, some scenarios were generated taking into account the data of climate change models (deltas) and the series observed in the basin stations.

When reviewing the precipitation projected by each of the models, it was concluded that some projects have an increase and others a decrease, having a possible percentage change between 21 and 14. However, the flow tends to decrease between 2 and 35% regardless of whether precipitation increases or not, given its relationship with other variables.

Given the above, the intention was to establish the sensitivity and vulnerability of the hydroelectric power generation system, creating scenarios based on the supply and demand of the area and the aforementioned climate projections. The scenarios were entered in the "Water Evaluation and Planning System-WEAP 2.1" and it was found that hydropower generation tends to decrease in the future, between 15 and 46%, which can increase the production costs that could be transferred to the users of this service. The above is summarized in **Table 5**.

This study indicates that research should be carried out in order to establish the potential vulnerability of systems related to supply and demand in this area under the influence of climate change. Therefore, a subsequent investigation was carried out in which it was considered that the impact on water resources was not only the result of the change in its offer or its quality, but also the pressure on the said offer in which the population and planning processes influence significantly [8].


*Effects of Climate Change on Water Resources, Indices, and Related Activities in Colombia DOI: http://dx.doi.org/10.5772/intechopen.90652*

#### **Table 5.**

Once the water balance has been carried out with the new weather conditions, it is clear that none of the classifications mentioned at the beginning of this section have changed (Lang and Thornthwaite). However, the conditions of such classification are exacerbated since there is a reduction in the Moisture Index (Im), which may have a negative implication, both ecologically and socially, due to the lower

This suggests that there is a growing need to investigate this area in order to develop an adequate plan that may include water harvesting projects or efficient crop irrigation systems that take into account the future demands and projected

The influence of climate change in this area of the country was analyzed, evaluating the supply-demand relationship. The activities related to hydroelectric power were taken into account in four investigations that will be briefly described

This area of the country is deserted due to the anthropic activity in the riverbed of the basin, in addition to the deforestation associated with different activities. It is a region of great importance for the country considering that approximately 66% of the electricity in Colombia is generated in hydroelectric plants [15] and that 3.7% of that value is a direct contribution of the Urra I system, located in the Sinú-Caribe basin. Moreover, it is susceptible to flooding; so the occurrence of extreme precipitation events is important for research related to climate change, considering that due to its influence the events will tend to be more frequent in

For the first investigation carried out in 2009 [7], the precipitation and temperature data were initially obtained for two weather stations in the area. Then, some statistical regressions were performed to establish the relationship between the mentioned variables and the flow measured in the basin. Regarding the future projection of precipitation and temperature, some scenarios were generated taking into account the data of climate change models (deltas) and the series observed in

When reviewing the precipitation projected by each of the models, it was concluded that some projects have an increase and others a decrease, having a possible percentage change between 21 and 14. However, the flow tends to decrease between 2 and 35% regardless of whether precipitation increases or not, given its

Given the above, the intention was to establish the sensitivity and vulnerability

This study indicates that research should be carried out in order to establish the potential vulnerability of systems related to supply and demand in this area under the influence of climate change. Therefore, a subsequent investigation was carried out in which it was considered that the impact on water resources was not only the result of the change in its offer or its quality, but also the pressure on the said offer

of the hydroelectric power generation system, creating scenarios based on the supply and demand of the area and the aforementioned climate projections. The scenarios were entered in the "Water Evaluation and Planning System-WEAP 2.1" and it was found that hydropower generation tends to decrease in the future, between 15 and 46%, which can increase the production costs that could be trans-

ferred to the users of this service. The above is summarized in **Table 5**.

in which the population and planning processes influence significantly [8].

precipitation deficits, to serve as a climate change adaptation strategy.

availability and access to drinking water.

*3.2.1 Sinú-Caribe basin*

*Resources of Water*

in this section.

the future [3].

the basin stations.

**78**

relationship with other variables.

**3.2 Effects of climate change on related activities**

*Changes in hydroelectric power generation and its related variables [7].*

A model was made using WEAP 2.1 software, to simulate hydrological processes in the scenarios concerning anthropogenic changes, land use, demands, and regulations among others. Its methodology is based on obtaining information on the daily consumption and activities in the study area, and their corresponding future increases based on projections. Then, it was contrasted with the reduction in supply due to environmental flow and quality considerations, as well as the possible variation in both temperature and precipitation and its consequent influence on the change in supply. Using WEAP, aspects of the supply-demand relationship were determined, such as unsatisfied demand, demand coverage, supply requirement, supply delivered, demand increase, and resource pressure indices. All scenarios are considered to be consistent with an increase in temperature and a positive or negative change in precipitation, as shown in Appendix 1, with a consequent decrease in the water flow or supply available.

As a result, it was concluded that in all scenarios it is not possible to supply the demand for water resources in all sectors and activities (commercial, industrial, rural, and urban areas), leading to a progressive growth of unsatisfied demand for the year 2039, as shown in **Figure 2**.

From this research, it is important to highlight the allocation of weights to climate change models based on their contribution to the flow, and their corresponding increase and decrease in temperature and precipitation respectively. Accordingly, a single weighted average scenario was proposed, where the worst possible scenarios are given a greater weight. Therefore, this scenario becomes a tool for planning water conservation strategies, such as the implementation of technologies for the reuse or efficient use of water, as well as the inclusion of vegetation conservation.

It was concluded that the proposed methodology and application of the WEAP tool allow to have a broader view of the resource in a region, allowing a better management of the water resource, with the possibility of planning strategies properly and taking into account adverse effects. This establishes the need to carry out a regionalization of climate change in order to develop tools that allow a detailed observation of its impact at local level. Finally, the inclusion of hydrological variables allows planning based on the water supply, reducing uncertainty in some way.

to carry out adaptation projects that take into account all the issues addressed in this section and the changes in the meteorological variables indicated in Appendix 1.

*Effects of Climate Change on Water Resources, Indices, and Related Activities in Colombia*

**3.3 Effects of climate change on water resources, indices, and related activities**

The municipality of Nilo, located in the department of Cundinamarca, is an important region for the production of Cocoa in Colombia. This study seeks to evaluate the water requirements for growing this product in current and future

For this purpose, a baseline was initially established in the period 1975–2005. Then, using variables such as precipitation, temperature, evapotranspiration, among others, a water balance was performed to recognize and characterize the study area, establishing adequate water availability, according to the water resource indices in **Table 6**. This procedure was repeated again considering the change in the

Additionally, the water requirements of the crop were established using CropWat software, climatic variables of the baseline and future scenarios, as well as

Consequently, crops were delimited due to water deficiency in soil, as a result of an increase in temperature (T) and a decrease in precipitation (PCP). The aforementioned will involve drought stress, a possible increase in pests, and a drastic reduction in crop yield. In addition, there will be a possible increase in the water deficit (Def) in both the pessimistic and optimistic scenarios, changing the Hydric Availability Index (HAI) in the area from optimal to semiarid, as shown in **Table 7**. According to the values in **Table 7**, in terms of the water requirements of the reference crop, a value of 359 mm for the baseline and a consequent increase up to

This study opens up the possibility of planning the use of the land, depending on the water requirements of both current and future crops, in order to make sustainable use of the water resource and can serve as a reference for new studies on this subject. This investigation measured the arithmetic average of the results obtained from the different models and scenarios. However, it does not allow observing the effect of each model, which may differ from each other, either in the magnitude of

> VH: Very humid H: Humid

> VH: Very humid H: Humid

M: Optimal ML: Semiarid L: Arid VL: Desert

MH: Moderately humid ML: Semiarid L: Arid VL: Desert

MH: Moderately humid

the change in temperature or in the increase or decrease in precipitation.

**Index Description Value**

deficiencies of water in specific areas or periods. It is a function of the relationship between the sum of the actual evapotranspiration and a quarter of the surpluses with the potential evapotranspiration [17]

LI The Lang's index describes the humidity conditions in the area as the ratio between average annual precipitation and average annual

HAI The Hydric availability index allows to identify surpluses or

some parameters related to soil, which were established based on fieldwork

projected meteorological variables for the years 2050 and 2070.

535 mm were established as a result of climate change.

*3.3.1 Nilo, Cundinamarca*

scenarios with climate changes [11].

*DOI: http://dx.doi.org/10.5772/intechopen.90652*

performed in the study area.

temperature [16]

*Description and assessment of the calculated indices.*

**Table 6.**

**81**

**Figure 2.** *Total unsatisfied demand, Sinú-Caribe basin [8].*

Having reviewed the supply-demand relationship in this area for different activities and considering the importance of hydroelectric power generation for the country, the need to propose a vulnerability index for this activity was established [9]. Based on the observed and projected data from the previous investigations, both for precipitation and temperature and for flow, as well as on the supply and demand data of the water resource, the WEAP tool was used again to perform a water balance that includes the data mentioned and the operating policies, technical problems, bathymetries, and evaporation in the basin.

Given the above, there is a direct relationship between the flow and the volume of the basin with changes in precipitation and temperature. Therefore, the vulnerability index will depend directly on these two variables, its lowest value being the result of a 10% increase in precipitation and a 0.5°C increase in temperature and the highest value the result of a 10% decrease in precipitation and a 3°C increase in temperature.

Given the cost overruns in energy production, research similar to the previous one supposes the possibility for decision-makers to establish the vulnerability of their systems to climate change, as well as to implement projects to adapt to and mitigate the effects.

Finally, it was intended to establish if the availability of water can act as an optimization factor in the generation of hydroelectric power [10]; so, an investigation focused on this topic was carried out. To do so, using both current and future supply and demand values, an adapted scenario was established in which demand decreases by 20% due to the efficient use of water. This makes the critical point at which demand equals supply more distant, having a difference of 5 years on average.

As for hydroelectric generation, some system optimization scenarios were established, including pumping from a downstream point of the basin to an upstream point, which regulates the basin and can be used to mitigate events of flood that, as mentioned, are very likely to occur. The optimization scenarios are contingent on pumping with different start dates and the amount of water extracted. It was established that pumping must begin before the critical point established for each demand scenario to avoid regional conflicts over the use of water.

However, from this latest investigation it was concluded that the critical point with measures such as pumping only takes a little longer to occur. Therefore, it is crucial to make changes in demand such as establishing appropriate water management and regulation strategies, optimizing water delivery infrastructure, and establishing priorities. This study and the previous ones encourage decision-makers to carry out adaptation projects that take into account all the issues addressed in this section and the changes in the meteorological variables indicated in Appendix 1.
