TY - JOUR

T1 - Representing a dense network of ponds and reservoirs in a semi-distributed dryland catchment model

AU - Rabelo, Udinart P.

AU - Dietrich, Jörg

AU - Costa, Alexandre C.

AU - Simshäuser, Max N.

AU - Scholz, Fernanda E.

AU - Nguyen, Van T.

AU - Lima Neto, Iran E.

N1 - Funding Information: We would like to thank the Foundation for Meteorology and Water Resources of the State of Ceará (FUNCEME) for making available the DEM, the raw information about the landscape properties and the meteorological time series and the Deutscher Akademischer Austauschdienst (DAAD) for supporting field work. We also thank the Water Agency of the State of Ceará (COGERH) and the Secretary of Water Resources of the government of Ceará (SRH) for providing reservoir data. Finally, we are grateful for the streamflow time series, which were made available by the Brazilian Water Agency (ANA). This study was supported by the Foundation for Scientific and Technological Development of the State of Ceará (FUNCAP) (PNE0112–00042.01.00/16), the Brazilian National Council for Scientific and Technologica Development (CNPq) (155814/2018–4) and by Deutscher Akademischer Austauschdienst (DAAD). Funding Information: This study was supported by the Foundation for Scientific and Technological Development of the State of Ceará (FUNCAP) ( PNE0112–00042.01.00/16 ), the Brazilian National Council for Scientific and Technologica Development (CNPq) ( 155814/2018–4 ) and by Deutscher Akademischer Austauschdienst (DAAD).

PY - 2021/12

Y1 - 2021/12

N2 - The mismatch between natural water availability and demand in dryland regions is overcome by reservoirs of different sizes with the purpose of storing water. The increase in population in dryland regions and the consequent growth in water demand expanded the construction of small reservoirs, generating in these regions a dense network of reservoirs, which increases the complexity of modeling these hydrological systems. For dryland watersheds modeling with daily time-step, the horizontal connectivity of the reservoir network needs careful representation in order to achieve acceptable model performance, including cumulative effects of reservoirs. However, the horizontal connectivity of reservoir networks is often less investigated in large-scale catchment models. This work presents an innovative way of implementing the dense-reservoir network into the widely used eco-hydrological model Soil and Water Assessment Tool (SWAT), with detailed representation of large and small reservoirs, and an extensive analysis about the cumulative impact of small reservoirs on the horizontal hydrological connectivity for large-scale dryland catchments. A two-fold cross-validation was used against streamflow at a catchment outlet and against in-catchment reservoir water levels. The model daily performance was acceptable despite the input data uncertainty, with good reliability for peak flow in wet years, for nonflow periods and for the rising limb of the hydrograph. The efforts in the parameterization of reservoirs and aggregation of ponds allowed a better analysis of the hydrological processes and their impacts in the catchment. The results showed that small reservoirs decreased the streamflow, but had a low impact on catchment retention and water losses, with 2% of water retention in wet years. However, the water retention reached 9% in dry years, which may worsen periods of water scarcity in the large reservoirs. The spatial representation of small reservoirs for a high-density network in the SWAT model and the results of the cumulative impact of small reservoirs may be relevant for a better understanding of hydrology in dryland catchments, and can be applied to catchments in similar climatic and socio-economic environments.

AB - The mismatch between natural water availability and demand in dryland regions is overcome by reservoirs of different sizes with the purpose of storing water. The increase in population in dryland regions and the consequent growth in water demand expanded the construction of small reservoirs, generating in these regions a dense network of reservoirs, which increases the complexity of modeling these hydrological systems. For dryland watersheds modeling with daily time-step, the horizontal connectivity of the reservoir network needs careful representation in order to achieve acceptable model performance, including cumulative effects of reservoirs. However, the horizontal connectivity of reservoir networks is often less investigated in large-scale catchment models. This work presents an innovative way of implementing the dense-reservoir network into the widely used eco-hydrological model Soil and Water Assessment Tool (SWAT), with detailed representation of large and small reservoirs, and an extensive analysis about the cumulative impact of small reservoirs on the horizontal hydrological connectivity for large-scale dryland catchments. A two-fold cross-validation was used against streamflow at a catchment outlet and against in-catchment reservoir water levels. The model daily performance was acceptable despite the input data uncertainty, with good reliability for peak flow in wet years, for nonflow periods and for the rising limb of the hydrograph. The efforts in the parameterization of reservoirs and aggregation of ponds allowed a better analysis of the hydrological processes and their impacts in the catchment. The results showed that small reservoirs decreased the streamflow, but had a low impact on catchment retention and water losses, with 2% of water retention in wet years. However, the water retention reached 9% in dry years, which may worsen periods of water scarcity in the large reservoirs. The spatial representation of small reservoirs for a high-density network in the SWAT model and the results of the cumulative impact of small reservoirs may be relevant for a better understanding of hydrology in dryland catchments, and can be applied to catchments in similar climatic and socio-economic environments.

KW - Dryland hydrology

KW - Hydrological connectivity

KW - Pond

KW - Reservoir

KW - SWAT

UR - http://www.scopus.com/inward/record.url?scp=85118480057&partnerID=8YFLogxK

U2 - 10.1016/j.jhydrol.2021.127103

DO - 10.1016/j.jhydrol.2021.127103

M3 - Article

AN - SCOPUS:85118480057

VL - 603

JO - Journal of hydrology

JF - Journal of hydrology

SN - 0022-1694

M1 - 127103

ER -