Abstract
Water reservoirs, in general, have been considered to be the major cause of reduction of downstream hydrological connectivity in channels. Therefore, this study analyzed the sensitivity of hydrological connectivity in the Orós Reservoir hydrographic basin by using the ResNet model, designed to simulate the processes involved in fluvial hydrological connectivity in environments with a high density of reservoirs. The analysis of hydrological connectivity was performed with the model ResNetM, which simulated hydrological processes and considered hydrological connectivity between the reservoirs, according to the criteria established in this research. To identify the main elements that affect hydrological connectivity, sensitivity analysis (SI) was performed of some input parameters of the model. The sensitivity analysis indicated that the modification of the topology of the reservoir network was the variable that presented the highest sensitivity to hydrological connectivity, with a sensitivity value of 1.07, followed by the runoff coefficient, which obtained a sensitivity of 0.8. The modification of the rainfall and of the reservoir storage capacity, showed an intermediate sensitivity, with values of 0.46 and 0.45, respectively. On the other hand, the parameters of potential evaporation and transmission loss showed the lowest sensitivity, obtaining values of 0.19 and 0.01, respectively. In conclusion, the runoff coefficient and the reservoir network (change in the reservoir number of the network) were the parameters evaluated with the highest sensitivity of hydrological connectivity. Thus, the alteration of the landscape by man provides significant changes in river navigation between the reservoirs in the basin.
Highlights
In the northeast region of Brazil, classified as a semi-arid region, the construction of reservoirs has been the main decision adopted by water resource managers and by the civil population in order to try to solve the problem of water scarcity in the region over time (Malveira et al, 2012; Toledo et al, 2014)
The variations of parameters k and P resulted in alteration of Hydrological Connectivity Indicator (HCI) in a “stable” rhythm, resulting in a linear tendency (Figure 2), in which a low slope refers to the axis of abscissas
In the case of transmission loss (k), the low sensitivity of hydrological connectivity is due to the short extension of the reaches
Summary
In the northeast region of Brazil, classified as a semi-arid region, the construction of reservoirs has been the main decision adopted by water resource managers and by the civil population in order to try to solve the problem of water scarcity in the region over time (Malveira et al, 2012; Toledo et al, 2014). There is one severe drought every decade, which sometimes lasts for many years (Araújo and Bronstert, 2015) - for example, from 2012 to 2015 (Marengo et al, 2017) This reservoir construction policy often occurs without any control or use of technical-scientific knowledge. Hydrological connectivity in channels or rivers has been evaluated by analysis of water flow continuity in their riverbeds For this purpose, a minimum flow rate index is used to characterize such hydrological connectivity (Brozovic et al, 2011; Fryirs, 2012; López-Vicente et al, 2013; Garbin et al, 2019). This flow can be measured by fluviometric methods, by injection dilution gauging (Burke, 2009) and by simulations in hydrological models (Döll et al, 2003; Hanasaki et al, 2010; Malveira et al, 2012; Sun et al, 2015). Lane et al (2009) highlight that hydrological models have a very important role in hydrological connectivity, as they enable temporal variation and structural connectivity to be checked
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Ambiente e Agua - An Interdisciplinary Journal of Applied Science
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
