Determination of field capacity in the Chibunga and Guano rivers micro-basins

Abstract

Background: The micro-basins of the Chibunga and Guano rivers are located within the sub-basin of the Chambo River, which starts at the thaw of the Chimborazo, crosses the cities of Guano and Riobamba, and ends in the Chambo River. These rivers are considered fluvial hydrological forces and geological limits of the aquifer, located in this sub-basin. For this reason, our investigation addressed the field capacity in the micro-basins of Chibunga and Guano rivers, to determine the maximum retention potential, i.e., the saturation of water in the soil. Methods: We investigated the change of precipitation to runoff through the correlations between the characteristics of the soil and its vegetation. We applied the Curve Number (CN) method introduced by the United States Soil Conservation Service (USSCS); this represents an empirical model, which relates the vegetation cover to the geological and topographic conditions of the soil. Along with the geographic information system, the model allows to represent the variation of runoffs for each micro-basin, according to the different land use categories, over the time frame from 2010 to 2014. Results: We found that the maximum retention potential is directly affected by CN values, representing the runoff potential. Highest values of 100 belong to the wetlands, urban area, snow, and water, as rain is converted directly into runoff, being impervious areas. The Guano river micro-basin possesses clay soil with CN of 78, the soil texture for eucalyptus forest is clay loam, and its CN value, 46, is the lowest of the data set. Knowledge of field capacity allows to properly evaluate the storage capacity of soil and water conservation. Conclusions: Results of this work will be useful in the quantification of the water balance, to determine the water supply and demand.

Influencia de la geomorfología y el caudal en la calidad del agua del río Guano, Ecuador

“…In the upper part of the river (P_RIVER 1), the flow is small; at point P_RIVER 2, it increases a little due to the effect of the runoff of the sector. From point P_RIVER 3 the flow decreases, because there are irrigation canals (Castillo-López et al, 2021;Mendoza et al, 2021;Quevedo, 2020). P_RIVER 4 and P_RIVER 5 show an increase in the flow due to the presence of a spring that again provides water to the river (Chidichimo et al, 2018).…”

“…In addition, the rate of population area corresponds mainly to the town of Guano, which sits on the banks of the river and is the one that shows the most significant interference in its quality. To determine the sampling points, vegetation and land use information (Mendoza et al, 2021) were analyzed (Table 1). The river was traversed from the upper part to the river mouth, corroborating what was identified in the characteristics of land use and vegetation data.…”

“…From this raster, the Spatial Analysis slope tool is used to spatially determine the Slope (Sc) in the basin. This is done in the ArcGis 10.1 software (Mendoza et al, 2021).…”

Evaluation of nitrate concentrations in groundwater of Llío and San Pablo, Guano – EC

“…Once this area was identified, the geological and stratigraphic description was made, determining the type of structure and rocks found in the subsoil of the aquifer, allowing to relate the composition of the rocks with the presence of nitrates in the water of Llío and San Pablo. In addition, the results obtained in the study of the Guano and Chibunga rivers (Mendoza et al, 2021), which determined the field and infiltration capacity, were used as a complementary part to understand the movement of water, to relate the presence of nitrate concentration in the infiltration process.…”

“…To define the anthropic areas and activities, the surrounding area was taken into account, indicating which are the direct and most intense anthropic activities that can influence the study area. These anthropic areas were determined by cartography, this information was used from several works carried out in the area of influence (Chidichimo et al, 2018;Mendoza, 2015;Mendoza et al, 2021;Procel, 2018).…”