Instrumentation and Measurement Technologies for Water Cycle Management

Instrumentation and measurement technologies are currently playing a key role in the monitoring, assessment and protection of water resources. The whole water sector involves multiple technological contexts for the monitoring of the resource, given the broad multidisciplinary context, which covers water from its natural domains up to the various man-made infrastructures.

The recent development of the Copernicus programme in Europe has ushered in a new generation of operational earth observing satellites. Field-based investigations and monitoring programmes are costly, time consuming and can be logistically challenging in remote or inaccessible locations. The advantages of in situ data monitoring are that they have very low uncertainties compared to satellite data, but they only provide readings at one location at one time. Satellite data are very complementary to field measurements for long-term and regional monitoring programmes. Through the Environmental Protection Agency (EPA)’s Remote Sensing of Irish Surface Water (INFER) project (2017-W-MS-30), we validated algorithms to infer lake water quality on the island of Ireland using Sentinel 2 imagery, which comprises two European Space Agency (ESA) terrestrial satellites with a combined temporal resolution of 5 days and spatial resolution of 10 m. The project is focused on the selection of optimal algorithms that will be applicable in a regional context in relation to the high cloud cover and relatively small sizes of the water bodies involved. C2RCC and Acolite processors were used to compute the chlorophyll-a and turbidity from identified lakes. Field radiometry was carried out using a TRIOS RAMSES radiometer at several sites to validate the algorithms. Standard field procedures were employed for acquiring glint-free reflectance from the water bodies. Based on the validation with field data, a coupled technique was developed to atmospherically correct and compute water quality parameters. The water quality products generated using Sentinel-2 can be visualized via a web platform (https://​eoplatform.​ichec.​ie/​infer). Although the developed techniques offer many benefits for water quality monitoring, it is still challenging in the context of Ireland, where very few cloud-free scenes are available. In addition, the smaller sizes of lakes make it difficult to monitor them using the current resolution of Sentinel-2.

Under the current Anthropocene Epoch there is an urgent need to deliver high‐quality data, information and knowledge to the decision-making process for a sustainable management of environmental concerns, in particular for inland water. Most literature address the advantages brought by remote sensing (RS) techniques in operational monitoring and management of lakes. In the present work, optical RS is applied to a complex ecosystem, the turbid eutrophic shallow Lake Trasimeno (Italy). A first example of RS application addresses the use of high frequency spectroradiometric measurements collected by a WISPstation to retrieve intra-inter daily and seasonal dynamics of chlorophyll-a and phycocyanin. A second section focuses on long term trends of water quality by means of satellite data time series for the whole lake surface. Then we exploit the latest generation of hyperspectral satellite images (PRISMA and DESIS) utilizing the high spectral resolution and improving the accuracy of estimated lake water quality. Finally, high spatial resolution satellite data is used for a finer scale mapping of bottom substrates. Application of these techniques improved scientific understanding on the timing, composition and distribution of phytoplankton blooms, the role of nutrients and climate drivers as well as changes in the extent and composition of aquatic plants.

The chapter provides a brief overview of satellite instrumentation, techniques and methods for oil spill detection on the sea surface. Monitoring of oil pollution from space is usually carried out using the synthetic aperture radars (SAR) and advanced synthetic aperture radars (ASAR) installed on satellites launched in different years by USA, ESA, USSR, Japan, Canada, Germany, and Italy. The first SAR system was installed on the SEASAT satellite launched on 27 June 1978, and since that time SAR systems showed their efficiency in oil spill detection on the sea surface. As any remote, in-situ or laboratory method, SAR remote sensing has a set of advantages (wide swath, all weather, day/night, daily periodicity, etc.) as well as disadvantages which include look-alikes caused by natural oceanic and atmospheric phenomena and processes, which need to be discriminated from oil pollution. Application of the SAR systems is illustrated by several examples of oil spill detection in different parts of the World Ocean and inland seas. Discussion of the assessment of total volume of oil pollution for the Baltic and Mediterranean seas shows that this is a difficult task and we still do not know real values of oil pollution of the marine environment. Development of scientific foundations and methodology for the quantitative assessment of environmental state of marine areas and of total amount of oil pollution of the World Ocean and inland seas is extremely urgent. Excessive human activity on the sea, including shipping, exploration and development of off-shore oil and gas reserves, construction and operation of underwater pipelines, platforms, terminals, storage facilities, ports, etc., entail very high risk of oil pollution in many sea areas.

The chapter provides a brief overview of satellite instrumentation, techniques and methods for monitoring of seawater quality (oil pollution, suspended matter, and algae bloom). Monitoring of oil pollution from space is usually carried out using the Synthetic Aperture Radar remote sensing systems, but under certain conditions, for example, in the zone of the sunglint, optical imagery is also very effective. Ocean color scanners are unique instrumentation for detection and monitoring of suspended matter (turbid waters) and chlorophyll-a (algae bloom) concentrations in the surface layer of the ocean. As any remote, in-situ or laboratory method, the ocean color scanners have a set of advantages (multispectral approach, high spectral resolution, high spatial resolution, etc.) as well as disadvantages which include dependence on the sunlight (there are no optical imagery during the night and Polar night) and clouds, dependence of the swath and repetition period on the spatial resolution of the sensor, etc. Application of the optical satellite remote sensing systems is illustrated by several examples of oil spill detection, turbid waters, and algal bloom in different seas of the World Ocean, and inland seas. Natural processes like wind-wave mixing in the coastal zone, river runoff, runoff from shallow lagoons, and algae bloom, as well as anthropogenic impact related to offshore and coastal mining, construction of ports and fairways, laying of underwater pipelines and cables, significantly impact seawater quality in the coastal zone of the World Ocean, and inland seas.

Hydrology, which is one of the oldest scientific disciplines, has experienced multiple technological and methodological breakthroughs over the last three decades. The advent of satellite radar altimetry have participated to a new range of applications in the monitoring of the continental water heights (on lakes, rivers, floodplains), in the study of global water cycle, and with a high range of scientific and societal applications. Satellite altimetry which was initially designed for oceanography has been widely used since the launch of Topex / Poseidon in 1992 in Hydrology because and it has allowed to calculate water height over the continental water bodies without restrictions, continuously, globally, regularly, and accurately. We present in this chapter the basics of the technics and how the data are processed, its forces and limitations, how it can be used together with other technics, how it can be assimilated into models, and what are the main outcomes over the last thirty years. Among hundreds of papers that are presenting applications of satellite altimetry in hydrology, we have done the choice to strengthen, what we believe are key studies that have left their mark on this discipline: Studies all centered on the use of satellite altimetry, for lakes, for rivers, for monitoring of artificial reservoirs, and how these measurements can be used in hydrological model in particular for studying ungauged basins.

The Climate Data Record (CDR) is a time series of measurements of sufficient length, consistency and continuity to determine climate variability and change. The generation of ECVs (Essential Climate Variables)/CDRs needs to put strong emphasis on the generation of fully described, error-characterized and consistent satellite-based ECV products (Zeng et al. in Remote Sensing 11:1–28, 2019). For example, generation of many ECVs, such as in the ESA (European Space Agency) CCI (Climate Change Initiative) projects (Plummer et al. in Remote Sens Environ 203:2–8, 2017), requires ancillary information about the state of the atmosphere, e.g., cloud screening for SST (sea surface temperature) and atmospheric correction for space-borne altimeters. As such, the consistency between the various ECV products (e.g. cloud flagged in one ECV and non-flagged in another one) extends to ensuring consistency in the approaches of CDR generation. The in-situ datasets also need to be continuously characterized in terms of their long-term accuracy, stability and homogeneity. Reanalysis results, as an alternative source of ECV, requires similar endeavors to investigate its consistency (Zeng et al. in Int J Appl Earth Obs Geoinf 42:150–161, 2015).

The occurrence of different contaminants in drinking water, surface water, domestic wastewater, and other water sources has led to increased interest in developing new methods and instruments for water quality monitoring able to provide adequate and rapid management interventions. A critical analysis of the main optical spectroscopy techniques for online water monitoring and their recent progress are presented. Not all spectroscopic techniques have yet reached a degree of maturity adequate for the purpose, however, even in these cases, their potentialities in this field are shown.

The structure and dynamics of the Vadose Zone (VZ) play a major role in the groundwater recharge process and in the transport of contaminants. By monitoring the mass and heat transfer processes within the VZ, it will be possible to predict the contaminants travel time and implement suitable solutions to preserve the groundwater resources. Several environmental monitoring solutions have been developed in recent years to better understand the complex hydrogeological processes that occur along the VZ. The use of Fiber Optic (FO) sensors is a promising technology for environmental monitoring. Compared to conventional sensors, the FO sensors allow measuring and monitoring different parameters, while offering interesting specificities. To improve our knowledge on the reactive processes occurring during mass and heat transfers within the VZ of the Beauce aquifer, the Observatory of transfers in the VZ is being developed near Orléans (France). Three types of distributed FO sensors (DTS, DSS and DAS) have been installed at the O-ZNS experimental site in July 2020. This chapter presents the state of the art on the use of FO sensors for environmental monitoring. The installation of these sensors at the O-ZNS site is then discussed along with the future developments and targeted results.

Plant transpiration accounts for about half of all terrestrial evaporation. Plants need water for many vital functions including nutrient uptake, growth and leaf cooling. The regulation of plant water transport by stomata in the leaves leads to the loss of 97% of the water that is taken up via their roots, to the atmosphere. Measuring plant-water dynamics is essential to gain better insight into its roles in the terrestrial water cycle and plant productivity. It can be measured at different levels of integration, from the single cell micro-scale to the ecosystem macro-scale, on time scales from minutes to months. In this contribution, we give an overview of state-of-the-art techniques for plant-water dynamics measurement and highlight several promising innovations for future monitoring. Some of the techniques we will cover include: gas exchange for stomatal conductance and transpiration monitoring, lysimetry, thermometry, heat-based sap flow monitoring, reflectance monitoring including satellite remote sensing, ultrasound spectroscopy, dendrometry, accelometry, scintillometry, stable water isotope analysis and eddy covariance. To fully assess water transport within the soil-plant-atmosphere continuum, a variety of techniques are required to monitor environmental variables in combination with biological responses at different scales. Yet this is not sufficient: to truly account for spatial heterogeneity, a dense network sampling is needed.

As far as Water is concerned, a lot of new directives and world concerns highlight among others the need for using ICT technologies, the global healthcare issues, the demand for fresh water, the food/beverage quality and safety, the environmental protection and the security strategies to reduce intentional contamination, all of the above having worldwide massive economic, natural and social impacts. However, despite an increasing demand for adaptability, compacity and performances at ever decreasing costs, the vast majority of water network monitoring systems remains based on sensor nodes with predefined and vertical applicative goals hindering interoperability and increasing costs (OPEX and CAPEX) for deploying new and added value services. Innovative technological products could answer the following acute needs in the field. This chapter introduce advance research works in sensing within two H2020 EU projects: the aqua3S project addressing sensors for Water Security purposes and LOTUS addressing low-cost multiparameter sensors for water quality.

Water management associations are responsible for monitoring large catchments and water bodies and thus have a great need for various hydrological measurement data. Most often, this comprises meteorological parameters as well as physical and chemical observations of water reservoirs, rivers and dams. In this context, low-cost sensors provide a great potential for densifying comprehensive monitoring systems. Typically, such a system requires the interoperable sharing of hydrological observation data as well as an efficient communication between the sensor devices. To establish smart water monitoring solutions, a sensor network infrastructure is needed that facilitates the management of a large amount of observation data and applies modern Internet of Things (IoT) communication approaches. This chapter aims to provide guidance in setting up a measurement data infrastructure that relies on both, standards of the well-established Sensor Web Enablement framework of the Open Geospatial Consortium (OGC) and IoT technologies. We introduce a concept for a modular water monitoring system that combines Sensor Web and IoT technologies to integrate sensor data in Spatial (Research) Data Infrastructures. Furthermore, the feasibility of this approach will be demonstrated with the presentation of an operational deployment at a German water management association.

This chapter is looking back on 20 years of online water quality monitoring, focussing on important achievements during that period, describe the current state of research and technology, and will take the oracle’s perspective at current and future trends. An overview of water monitoring topics is given, by method, measured substance, instrument, and by their applications. Focus is on substances of special environmental or health concern that can be detected by “solid state” sensors, and on applications that are a bit off the beaten monitoring track, to get a feeling for the always widening domain of on-line and real-time water quality monitoring.

The design of optimal monitoring networks at catchment level is both a challenge and an opportunity in the smart city era. New knowledge, information and services can be built by integrating diverse multimodal data streams, at scales appropriate to inform effective decision making. To this end a comprehensive, integrated hierarchical platform is ultimately required for fusing, gathering and analysing large volumes of data. Such workflows could include hydrological and geospatial data, land-use and activity data, remote data from aerial and space-borne platforms and in-situ data from both fixed and mobile platforms. In this context, this chapter aims to provide insight into how the future catchment monitoring platforms might look like and to synthesize and review recent technological progress. Emphasis is placed on the realisation of fit-for-purpose cost effective catchment monitoring programmes with immediate opportunity for implementation and state-of-the art emerging technologies are discussed in this context. In the first part, commercially available in-situ sensor technologies are reviewed to provide a starting point for users in the critical sensor selection process. A classification is provided based on operation principle while drawbacks and benefits are presented. Practical considerations, relating to monitoring requirements, deployment strategy, and cost are discussed to aid practitioners in the design of water quality monitoring networks. In the second part, aerial and satellite remote sensing platform are reviewed and constrains and technological limitations are presented. Examples of successful use of combined monitoring approaches are discussed with an emphasis on early warning and forecasting of pollution events. Technological gaps that should be filled to achieve an ideal catchment observation system are identified.

We review the application of the Spectral Induced Polarization (SIP) imaging method to delineate the geometry of hydrocarbon contaminant plumes and monitor the effect of remediation measures. In the first two sections, we present a brief introduction into the SIP method and discuss the electrical properties of the rocks and soils. In the third section, we offer a detailed revision of the literature to illustrate the broad range of electrical properties of fresh and mature contaminant plumes. In the fourth and fifth section, we discuss challenges and good practices for collection, processing and interpretation of SIP imaging data, and illustrate these steps with a real-case example regarding the characterization of a benzene plume. Along this case study, we demonstrate how the occurrence of benzene in the dissolved plume and in free-phase changes the electrical conductivity and polarization properties of the contaminated subsurface materials. A second case study deals with SIP monitoring results obtained along the injection of zero-valent iron particles for the remediation of a TCE (Trichloroethylene) plume. This example illustrates the advantages of the SIP method to evidence changes in the pore-space, such as clogging and fracking, which may affect the effectivity of remediation measures.

The climate change has dramatically decreased the useful freshwater resources so raising the probability of severe droughts. Near-surface geophysics uses the investigational methods of geophysics leading to their massive use in all scientific sectors (geology, hydrogeology, engineering, archaeology, environmental problems). Moreover, the increasing challenge of quantifying extractable, economically viable, potable water supplies has led to the definition of a new subdiscipline of hydrology known as hydrogeophysics. Direct current (DC) electrical methods are probably the most widely used near surface geophysical techniques for environmental investigations. DC methods are increasingly used in different approaches to cover a larger field of applications. In hydrogeological applications, the electrical resistivity distribution can provide important information that allows to characterize the heterogeneity of the aquifers and soil, to reconstruct the geometry of the aquifers and/or waterproof, to study the relationships between freshwater and seawater, or from groundwater different salinity.

A drone-based ground-penetrating radar (GPR) is introduced for digital soil mapping in this chapter. The radar system is lightweight and consists of a handheld vector analyzer (VNA), a computer stick, and a differential GPS for positioning. A power bank is used to provide electricity for the whole radar system. A smartphone or tablet controls the radar and GPS measurements remotely. Full-wave inversion is used to retrieve the soil dielectric permittivity from the soil surface reflection, hereby to estimate volumetric soil water content through a petrophysical relation. The radar works in the frequency domain, and data processing is carried out in the time domain to focus on the surface reflection only. A look-up table (LUT) is pre-calculated to reduce the processing time during inversion, formulated as a least-squares problem. Soil moisture maps are generated by kriging interpolation. We present several examples of soil moisture maps produced in agricultural fields in Belgium.

In the last decades, many efforts have been dedicated to improve direct and indirect methodologies to study and monitor the aquifers. In particular, seismic method was successfully applied for this purpose. In this work a case study in the North East of Italy is described, for which seismic data were acquired and analyzed to characterize an aquifer system. All the phases of the experiment are illustrated, from the choice of the acquisition parameters to the final interpretation. Both 2D and 3D data were acquired in different seasons in order to define any possible seasonal variation. In order to obtain detailed petrophysical information, amplitude preserving processing, advanced tomographic imaging and Amplitude Versus Offset procedures were used. This analysis enabled to estimate the petro-physical properties of the subsoil and to locate a deeper aquifer not yet identified, as confirmed by a subsequent new well. The discovered aquifer, at 480 m depth, has been proved to be suitable for capturing for domestic purposes.

The deciphering of the coupled processes that govern the transfers of mass and heat within the vadose zone is recognized as a complex issue. In this context, an observatory of transfers in the vadose zone (O-ZNS) has been implemented near Orléans (France). By combining multiscale laboratory and field experiments using various monitoring techniques, this observatory will improve our knowledge regarding water flow and contaminant transport throughout the 15–19 m highly heterogeneous vadose zone. To image the lithological and hydraulic properties of its heterogeneous facies, we adopted a multi-geophysical monitoring strategy in order to overcome the limitations of each individual geophysical method. This approach includes surface, borehole, and well multi-geophysical measurements. Preliminary investigations undertaken since 2017 leads to an effective and complete characterization of the vadose zone including (i) a lithological description of the geological facies, (ii) the identification of local heterogeneities (karsts, fractures, silicified layers) whose density increases with depth, and (iii) an estimation of the water content variations within the vadose zone. This whole set of results constitutes a first base to ongoing joint inversion that should lead to a refined characterization of the petrophysical and transport properties of the vadose zone column.

In this contribution the main electromagnetic techniques exploited for the measurement of the dielectric permittivity of a material under test (MUT) are resumed, with particular emphasis on the technique of the Time Domain Reflectometry (TDR). In this framework, we propose also an innovative multilength TDR strategy, in order to achieve more information on the MUT, even at single frequency. This can help for the measure of the dispersion law of the materials, that can be a sort of signature of that material with respect to its moisture content and possibly with respect to the inclusion of some polluting substance melted in it.

Water is an essential natural resource for assuring life and its effective usage and distribution is a key issue made more and more relevant by climate changes. This framework supports the development and employment of technological solutions devoted to improve water management through a growth of the efficiency of the network and distribution systems. In this frame, Ground Penetrating Radar (GPR) deserves attention being a portable, low-cost, non-invasive and high reliability technology suitable for water pipe monitoring and leak detection. Accordingly, the chapter reviews advantages and limits featuring GPR. Moreover, it proposes a data processing approach to improve GPR imaging and provides a proof of concepts assessing its reconstruction capability preliminarily.

In this chapter we present a brief description of hydrogeophysical methods and their history over the past twenty years, with specific reference to their application for water resources protection and management. This generally requires that geophysical methods, and electrical/electromagnetic methods in particular, are used in time-lapse mode, thus allowing us to monitor hydrological changes in the subsurface. These data, in turn, can be used for calibration of hydrological models or for a better conceptualization of the subsurface hydrological processes. This can be done at a large variety of scales, even though here we present cases relevant to the small to intermediate scale. Examples concerning soil, vadose zone, hillslope and hydrogeological processes are shown and discussed.

The Sea of Galilee (Lake Kinneret) is located in northern Israel in a complex tectonic setting where the Dead Sea Transform crosscuts other fault systems. The practical absence of boreholes in the sea hinders geological-geophysical data interpretation. For the first time, gravity, magnetic, paleomagnetic, radiometric, and seismological data were analyzed together. An integrated analysis of gravity and seismological data made it possible to clarify some tectonic parameters. The total magnetic field map shows an intricate pattern caused by a combined influence of the basalt flows of various ages and magnetization in and around the sea. Calculated statistical-probabilistic parameters of the magnetic field indicate some essential peculiarities of the medium. The recognized magnetic anomalies were analyzed using methods of quantitative interpretation especially developed for the complex physical-geological environments. 3D magnetic field modeling allowed to reveal the following important features: thick basaltic plate occurrence in the southernmost sea basin, presence of the reversely magnetized basalts near the sea’s eastern boundary, and possible subsidence of basaltic bodies in the center of the pull-apart basin. The paleomagnetic stratigraphy of basalt associations around the Sea of Galilee basin proved to be correlated with the paleomagnetic zones and anomalies in the sea. The paleomagnetic characteristics of traps are linked with the development of the Dead Sea Transform. The previously constructed magnetic-paleomagnetic scheme with predominantly K–Ar dating has been significantly elaborated on the basis of newly arriving data. It is stated that a characteristic feature of the study area is the turns of tectonic blocks, mainly counterclockwise. The revised structural map of the Cover Basalts is intended to coordinate various geological and environmental investigations in this area.

Stochastic hydrology can be a powerful instrument to quantify uncertainty in complicated geological structures, since numerical models must accommodate high levels of material heterogeneity. The possibility to provide for the behavior of groundwater systems under specific conditions, thanks to a realistic representation of the hydraulic properties and geometries in a mathematical model, is the basis for a conscious management of engineering, economic, social and political problems which are typical of remediation actions. The composite media theory which allows the estimation of the spatial distribution of multiple materials, even when the medium is highly heterogeneous, is presented. The probabilistic reconstruction of boundaries between geologic facies is applied to the mathematical model of the contaminated aquifer involved by the industrial site of the city of Naples. Sedimentologic information led to the identification of different types of geomaterials, whose spatial variability is analyzed through the indexed variables approach. The hydraulic conductivity distribution is then estimated through a geostatistical analysis, and the values are calibrated as a function of the observed hydraulic heads. The realistic reconstruction of the morphology and the hydrodynamic characteristics of a polluted site within a modeling tool, gives a fundamental help to design efficient remediation processes, without causing unacceptable perturbation of the natural conditions of the sites and excessive costs.