University of Twente Student Theses


Exploring the potential of high-resolution soil moisture indicators for decision-making in regional operational water management

Heus, L.C.A.V. de (2019) Exploring the potential of high-resolution soil moisture indicators for decision-making in regional operational water management.

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Abstract:Water systems face an increasing pressure due to climate change and socio-economic developments. This emphasizes the need for rational and reliable information for decision-making in water management. In this MSc. study, soil moisture indicators are defined and validated to translate soil moisture data into information which can support decision-making in Dutch regional operational water management. Soil moisture is water in the pores between soil particles above the groundwater level. Although soil moisture is categorized as an Essential Climate Variable (ECV) by the European Space Agency, this variable is currently not applied for decision-making in water management, which is related to the lack of soil moisture data and perception of its importance in water management. The motivation for this study is the availability of new soil moisture data, for example from Sentinel-1 satellite data. First, a theoretical framework is constructed to acquire insight in methods to bridge the science-policy gap. The outcomes are used to identify the information demand of water managers from the operational water management crisis team WOT (Waterschap Operationeel Team) of regional water authorities Vechtstromen and Drents Overijsselse Delta. The WOT is active among others in dry and wet periods and aims at mitigating the impact of extreme periods. The information demand of the water managers is identified by means of a survey, which contained two case studies concerning an extreme dry and an extreme wet case. The results of survey obtained insight in the following practical demands: insight in the storage capacity of the unsaturated zone, availability of water for crops, spatial information that distinguishes wet (or dry) and extreme wet (or dry) areas and specifications regarding the spatio-temporal resolution. These practical demands from water managers are merged with requirements that indicators should meet from a scientific perspective. These indicator requirements consist of data availability, accuracy, reliability, relevance, temporal and spatial resolution and translation (data into information). These requirements are used to develop indicators in this study and to select suitable indicators based available soil moisture indicators found in literature. To quantify the indicators, hydrological model data are used, because root zone and unsaturated zone soil moisture data cannot be retrieved by satellite measurements. Three indicators comply with the requirements, namely the Storage Capacity Indicator (SCI), Soil Water Deficit Index (SWDI) and Soil Water Wetness Index (SWWI) of which the latter is developed in this study. The SWDI and SWWI classify the severity of dry and wet conditions respectively, whereas the SCI depicts the available storage of the soil. This SCI can be used in combination with precipitation forecasts to predict whether the precipitation amount can be stored in the soil. These indicators are validated by means of a workshop with employees of regional water autority Vechtstromen. During the workshop, the participants considered the currently used information in operational water management accurate and easily interpretable. However, these information sources do not provide full insight in the water system. This means that water managers do not have all relevant information about the water system at their disposal yet. Therefore, they indicated earlier that there is a demand for more information. The participants stated that soil moisture data can offer new insights in the water system and can have a positive supporting value of the current insights. The soil moisture indicators that were used in this study were also valued positive with regard to the ease of use of the data, which means the application of indicators has potential in the translation of data into information. Therefore, soil moisture indicators may play a role in providing water managers new insights in the water system. As a side note, the usefulness of the soil moisture data and indicators in regional operational water management cannot be derived directly from the workshop, because they are not quantitatively applied in a case study to measure the impact of the indicators on decision-making. To build upon the positive attitude of the participants of the workshop regarding soil moisture data and indicators, it is recommended to explore the integration of the data and indicators in operational water management. To enhance the water managers’ understanding of the water system, a participative approach might be helpful. It is suggested to take four steps into account during this integration process. The first step involves the water managers gaining experience with the new soil moisture data and indicators. The second step focuses on the detection of trends and patterns in the soil moisture indicators to improve understanding in the water system. The third step concerns the water managers being allowed to adapt the classification structure of the indicators towards their perception in practice. After a positive result of the first three steps, the fourth step follows. This step comprises that soil moisture indicators might be part of a decision tool on which measures in the water system can be based.
Item Type:Essay (Master)
Faculty:ET: Engineering Technology
Subject:56 civil engineering
Programme:Civil Engineering and Management MSc (60026)
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