River model calibration, from guidelines to operational support tools

Abstract

Manuscript AbstractNumerical modelling is now used routinely to make predictions about the behaviour of environmental systems. Model calibration remains a critical step in the modelling process and different approaches have been taken to develop guidelines to support engineers and scientists in this task. This article reviews currently available guidelines for a river hydraulics modeller by dividing them into three types: on the calibration process, on hydraulic parameters, and on the use of hydraulic simulation codes. The article then presents an integration of selected guidelines within a knowledge-based calibration support system. A prototype called CaRMA-1 (Calibration of River Model Assistant) has been developed for supporting the calibration of models based on a specific 1D code. Two case studies illustrate the ability of the prototype to face operational situations in river hydraulics engineering, for which both data quality and quantity are not sufficient for an optimal calibration. Using CaRMA-1 allows the modeller to achieve the calibration task in accordance with good calibration practice implemented in the knowledge base. Relevant reasoning rules can easily be added to the knowledge base to extend the prototype range of applications. This study thus provides a framework for building operational support tools from various types of existing engineering guidelines.

HESS Opinions: Advocating process modeling and de-emphasizing parameter estimation

“…These latter two (conformity with organizing principles and water balance scheme) are particularly relevant when attempting to develop a community hydrological model (Weiler and Beven, 2015) or a hyper-resolution model of everywhere (Beven, 2007;Beven et al, 2015;Beven and Alcock, 2012). Such constraints and relational rules can either be applied manually or by some computer-based procedure (see Gharari et al, 2014;Vidal et al, 2007).…”

“…Those parameters having constraints and relational rules are allocated together. The constraints can be either implemented manually or by using simple computer codes in the case of automatic procedure (see, for example, the tool presented by Vidal et al, 2007).…”

“…In other work, Vidal et al (2007) reviewed the process of calibrating physically based models such as river hydraulic models and distributed hydrological models, with a special emphasis on knowledge base calibration. They criticize the fact that calibration is often done without any or with only minimal physical consideration.…”

Flow Resistance Analysis for Lower Naesung Stream Considering Grain and Bedform Roughness

“…하천계획 수립시 Manning 조도계수는 주로 구 간 규모로 추정되고 있으며 (Lee et al, 2007), 구간 조도계 수를 추정하는 방법은 실측자료를 이용한 조도계수 산정 방법, 국내외 현장사진이 포함된 조도계수 자료집과 비교 하는 방법, 하상재료의 특성에 따른 경험식으로 산정하는 방법 등이 있다 (Kim et al, 2007a), 한편 Kim et al (2011) 은 하천의 기초 자료조사가 부족한 국내 하천여건상 수리 학적 모형을 이용한 방법이 객관적이고 정확한 방법임을 제시하였다. 실제로 홍수사상에 대한 실측자료가 충분히 가용할 경우, 계산 수위와 실측 수위가 서로 일치하도록 구간 조도계수를 조정하여 수치모형을 보정하고 검증하 는 방법은 국내외적으로 일반적인 방법이다 (Kim et al, 1995;Vidal et al, 2007;Kim and Kim, 2013). Bae et al (2012) 충적하천의 경우 하상형태와 조도는 시간에 따라 변동 되며 이러한 하상변화와 조도계수의 변화를 정량적으로 산정하는 것은 매우 어려운 문제이다 (Wu and Wang, 1999).…”

Modelling the transition from dunes to the upper-stage plane bed

“…Hydraulic roughness values play an important role in correctly determining water levels (Casas et al, 2006;Vidal et al, 2007;Morvan et al, 2008), which is critical for flood management purposes. River dunes increase the hydraulic roughness significantly, because their shape causes form drag.…”