title: Trade-off between reservoir yield and evaporation losses as a function of lake morphology in semi-arid Brazil.
abstract: This study investigates the relationships between yield and evaporation as a function of lake morphology in semi-arid Brazil. First, a new methodology was proposed to classify the morphology of 40 reservoirs in the Ceará State, with storage capacities ranging from approximately 5 to 4500 hm3. Then, Monte Carlo simulations were conducted to study the effect of reservoir morphology (including real and simplified conical forms) on the water storage process at different reliability levels. The reservoirs were categorized as convex (60.0%), slightly convex (27.5%) or linear (12.5%). When the conical approximation was used instead of the real lake form, a trade-off occurred between reservoir yield and evaporation losses, with different trends for the convex, slightly convex and linear reservoirs. Using the conical approximation, the water yield prediction errors reached approximately 5% of the mean annual inflow, which is negligible for large reservoirs. However, for smaller reservoirs, this error became important. Therefore, this paper presents a new procedure for correcting the yield-evaporation relationships that were obtained by assuming a conical approximation rather than the real reservoir morphology. The combination of this correction with the Regulation Triangle Diagram is useful for rapidly and objectively predicting reservoir yield and evaporation losses in semi-arid environments.
authors.affiliation: Departamento de Engenharia Hidráulica e Ambiental, Universidade Federal do Ceará/ UFC, Campus do Pici, Bl. 713, 60451-970 Fortaleza, CE, Brasil, Universidade Federal do Ceará, Universidade Federal do Ceará, Departamento de Engenharia Hidráulica e Ambiental, Fortaleza CE , Brasil.
authors.forename: José N B
authors.initials: JN
authors.lastname: Campos
authors.affiliation: Departamento de Engenharia Hidráulica e Ambiental, Universidade Federal do Ceará/ UFC, Campus do Pici, Bl. 713, 60451-970 Fortaleza, CE, Brasil, Universidade Federal do Ceará, Universidade Federal do Ceará, Departamento de Engenharia Hidráulica e Ambiental, Fortaleza CE , Brasil.
authors.forename: Iran E
authors.initials: IE
authors.lastname: Lima
authors.affiliation: Departamento de Engenharia Hidráulica e Ambiental, Universidade Federal do Ceará/ UFC, Campus do Pici, Bl. 713, 60451-970 Fortaleza, CE, Brasil, Universidade Federal do Ceará, Universidade Federal do Ceará, Departamento de Engenharia Hidráulica e Ambiental, Fortaleza CE , Brasil.
authors.forename: Ticiana M C
authors.initials: TM
authors.lastname: Studart
authors.affiliation: Departamento de Engenharia Hidráulica e Ambiental, Universidade Federal do Ceará/ UFC, Campus do Pici, Bl. 713, 60451-970 Fortaleza, CE, Brasil, Universidade Federal do Ceará, Universidade Federal do Ceará, Departamento de Engenharia Hidráulica e Ambiental, Fortaleza CE , Brasil.
authors.forename: Luiz S V
authors.initials: LS
authors.lastname: Nascimento