# The Hydroological Balance in Micro-Watersheds Is Affected by Climate Change and Land Use Changes
## 3 Results and Discussion
### Hydrological Balance
#### 3.4.1 Projections of Future Hydrological Conditions
With the increase in forest cover, there would be a smaller speed of runoff [72; 82]. It was also observed that in the inflows by 2081-2100, there would be an average increase in the three microbasins of the water stored in the soil the previous year: 60.9% (CNRM), 41.9% (HadGEM3) and 31.3% (MPI), which for all the study area represents 53.7% more than that in the percentages of the scenarios under the conditions of the negative scenario of land use change. This input will increase water infiltration and recharge of aquifers [83]. An average increase in evapotranspiration of 37.9% (CNRM), 34.2% (HadGEM3), and 22.3% (MPI) would also be expected to be directly related to the increase in temperature and forest cover [84]. The hydrological balances under the conditions of the negative scenario of land use change were simulated with a decrease of 50.1% of forest cover due to the persistence of high-severity forest fires; additionally, these fires would cause a decrease of 81.7% of reforestation and would not allow the establishment of the natural regeneration of the forest. Therefore, in degraded areas, there would be a significant advance of rainfed agriculture (64.2%), preferably forest. The model indicates that surface runoff would increase under these conditions [60; 63] in the three micro-watersheds: Chapingo River (332.1%, 187.8%, and 140.6%), Texcoco River (355.6%, 184.2%, and 142.4) and San Bernardino River (326.1%, 190.8% and 140.1%) according to the CNRM, HadGEM3, and MPI, respectively. Water stored in the soil decreased by \(-\)22.5% compared to the previous year (CNRM), \(-\)25.5% (HadGEM3), and \(-\)34.9% (MPI) for the Chapingo River would also be expected, and \(-\)6.4% (CNRM), \(-\)8.7% (HadGEM3) and \(-\)20.6% (MPI) for the San Bernardino River. The ability of the soil to store and control the flow of water depends largely on its penetration rate and depth, but disturbances such as changes in land use and fire are capable of altering the rate of these soil capacities [85]. These alterations occur because the soil is exposed to water erosion, compaction [86], and alterations in structure (disappearance of organic matter and microfauna, lower field capacity, and higher apparent density) [85]. The modification of these flows suggests that the availability of water that provides the hydrological ecosystem service will be compromised in the study area [87]. However, in the Texcoco River basin, the three models indicate increases of 23.8%, 9.5%, and 3.9%, respectively, in this inflow. This result may be related to the increase in the estimation of precipitation by the GCMs. Although actual evapotranspiration is significantly related to the proportion of forest cover [88], despite the decrease in the forest according to the conditions of the negative scenario, the three models indicate an average increase in evapotranspiration in the three micro-watersheds: 24.8%, 24.2%, and 13.7%, respectively. This result could be related to the increase in precipitation and temperature values by the GCMs and may also be related to the modification of the hydrological balance [63; 89].