Water Resour Manage (2018) 32:3041–3052
https://doi.org/10.1007/s11269-018-1973-x
Probabilistic Model for the Representation
of the Reservoir Water Level of Concrete Dams During
Normal Operation Periods
Renato Pereira
1
· Ant
´
onio Lopes Batista
2
·
Lu
´
ıs Canhoto Neves
3
Received: 28 June 2016 / Accepted: 26 March 2018/
Published online: 3 April 2018
© Springer Science+Business Media B.V., part of Springer Nature 2018
Abstract The dam’s reservoir water level varies over the year according to the water inflow
and outflow, as a function of environmental events but also of dam exploitation management
policy and human decisions. In the Portuguese dam safety regulation (RSB 2007), the nor-
mal water level (NWL) is considered as the optimum exploitation level. However, as proved
by the continuous monitoring over the lifetime of a set of dams, the NWL is occasion-
ally exceeded for non-negligible time periods. The reservoir water level, to which the water
pressure on the upstream face is related, is a fundamental parameter for the safety and reli-
ability analysis of concrete dams. When water-induced actions are considering the leading
loads, only the maximum reservoir water level, usually associated with a high-return-period
flood, is relevant. However, for other combinations, in particular, earthquake scenarios, the
consideration of the variability of the water level over time is crucial. In reliability analy-
sis of concrete dams, the reservoir water level has been considered either as a deterministic
variable, once the loading scenario analyzed assume water-induced actions as leading loads
(Westberg 2010), or as a random variable defined using hydrological site information of
a specific study case (Altarejos et al. Structural Safety 36-37:1–13 2012). This work pro-
poses a probabilistic model of the reservoir water level of any new dam based only on its
geometrical properties, which provides a low-cost alternative to in-depth hydrological anal-
ysis. The proposed model can be useful in two stages of the lifecycle of dams: (i) initial
design and feasibility stages, and (ii) routine safety assessment of existing structures, as in
Renato Pereira
r.pereira@campus.fct.unl.pt
1
Departamento de Engenharia Civil, Faculdade de Ci
ˆ
encias e Tecnologia, Universidade Nova de
Lisboa, Quinta da Torre, 2829-516, Caparica, Portugal
2
Departamento de Barragens de Bet
˜
ao, Laborat
´
orio Nacional de Engenharia Civil, Av. Brasil 101,
1700-066, Lisboa, Portugal
3
Department of Civil Engineering, University of Nottingham, University Park, Nottingham NG7
2RD, UK
@Phil_Robichaud
@deepthiw
@JoseServera