Sediment Transport in the Koiliaris River of Crete

AbstractIn this paper, a study of the sediment transport in a complex Mediterranean watershed (i.e. the Koiliaris River Basin of Crete) consisting of temporary flow tributaries and karstic springs is presented. Both daily flow data (2005-2013) and monthly sediment concentration data (2011-2013) were used to calibrate the modified Soil and Water Assessment Tool (SWAT) model, designed to simulate the hydrology, sediment yield and water quality of ungauged watersheds, and augmented with a karst flow model in order to simulate the contribution of the extended karst to the spring discharge in the basin. The results showed good agreement between observed and model values for both flow and sediment concentration. However, since no data representative of high sediment concentration conditions were available, such as during extreme flow events, an automated sediment sampling device (Sediment Trap), which allows for flow weighted sampling, has been developed and is detailed in this paper. This device is undergoing testing to ensure it can provide accurate estimates of sediment yield, especially during a flush flood event when large amounts of sediment are carried downstream. The sediment measurements will then be used to calibrate and verify the sediment transport simulations of the Koiliaris River watershed generated by the SWAT model. The sediment transport simulations and the development of the automated sampling device were part of the preliminary work for the pilot application of the “Cybersensors” infrastructure in the Koiliaris River. The Cybersensors research project aims to develop an intelligent integrated monitoring system, which will utilize electrochemical and optical sensors, and will allow for high-frequency monitoring of the physical and chemical parameters of a river flow and thus the rapid detection of environmental change during episodic events, as well as for long term monitoring

Assessing the freshwater quality of a large-scale mining watershed : the need for integrated approaches

Water quality assessments provide essential information for protecting aquatic habitats and stakeholders downstream of mining sites. Moreover, mining companies must comply with environmental quality standards and include public participation in water quality monitoring (WQM) practices. However, overarching challenges beyond corporate environmental responsibility are the scientific soundness, political relevance and harmonization of WQM practices. In this study, a mountainous watershed supporting large-scale gold mining in the headwaters, besides urban and agricultural landuses at lower altitudes, is assessed in the dry season. Conventional physicochemical and biological (Biological Monitoring Water Party-Colombia index) freshwater quality parameters were evaluated, including hydromorphological and land-use characteristics. According to the indicators used, water quality deterioration by mining was absent, in contrast to the effects of urban economic activities, hydromorphological alterations and (less important) agricultural pollutants. We argue that mining impacts are hardly captured due to the limited ecological knowledge of high-mountain freshwaters, including uncharacterized mining-specific bioindicators, environmental baselines and groundwater processes, as well as ecotoxicological and microbial freshwater quality components. Lessons for overcoming scientific and operational challenges are drawn from joint efforts among governments, academia and green economy competitiveness. Facing a rapid development of extractive industries, interinstitutional and multidisciplinary collaborations are urgently needed to implement more integrated freshwater quality indicators of complex mining impacts

The impact of agricultural activities on water quality: a case for collaborative catchment-scale management using integrated wireless sensor networks

The challenge of improving water quality is a growing global concern, typified by the European Commission Water Framework Directive and the United States Clean Water Act. The main drivers of poor water quality are economics, poor water management, agricultural practices and urban development. This paper reviews the extensive role of non-point sources, in particular the outdated agricultural practices, with respect to nutrient and contaminant contributions. Water quality monitoring (WQM) is currently undertaken through a number of data acquisition methods from grab sampling to satellite based remote sensing of water bodies. Based on the surveyed sampling methods and their numerous limitations, it is proposed that wireless sensor networks (WSNs), despite their own limitations, are still very attractive and effective for real-time spatio-temporal data collection for WQM applications. WSNs have been employed for WQM of surface and ground water and catchments, and have been fundamental in advancing the knowledge of contaminants trends through their high resolution observations. However, these applications have yet to explore the implementation and impact of this technology for management and control decisions, to minimize and prevent individual stakeholder’s contributions, in an autonomous and dynamic manner. Here, the potential of WSN-controlled agricultural activities and different environmental compartments for integrated water quality management is presented and limitations of WSN in agriculture and WQM are identified. Finally, a case for collaborative networks at catchment scale is proposed for enabling cooperation among individually networked activities/stakeholders (farming activities, water bodies) for integrated water quality monitoring, control and management

Arctic–CHAMP: A program to study Arctic hydrology and its role in global change

The Arctic constitutes a unique and important environment that is central to the dynamics and evolution of the Earth system. The Arctic water cycle, which controls countless physical, chemical, and biotic processes, is also unique and important. These processes, in turn, regulate the climate, habitat, and natural resources that are of great importance to both native and industrial societies. Comprehensive understanding of water cycling across the Arctic and its linkage to global biogeophysical dynamics is a scientific as well as strategic policy imperative

Arctic–CHAMP: A program to study Arctic hydrology and its role in global change

The Arctic constitutes a unique and important environment that is central to the dynamics and evolution of the Earth system. The Arctic water cycle, which controls countless physical, chemical, and biotic processes, is also unique and important. These processes, in turn, regulate the climate, habitat, and natural resources that are of great importance to both native and industrial societies. Comprehensive understanding of water cycling across the Arctic and its linkage to global biogeophysical dynamics is a scientific as well as strategic policy imperative

Bridges Structural Health Monitoring and Deterioration Detection Synthesis of Knowledge and Technology

INE/AUTC 10.0

Development and deployment of a microfluidic platform for water quality monitoring

There is an increasing demand for autonomous sensor devices which can provide reliable data on key water quality parameters at a higher temporal and geographical resolution than is achievable using current approaches to sampling and monitoring. Microfluidic technology, in combination with rapid and on-going developments in the area of wireless communications, has significant potential to address this demand due to a number of advantageous features which allow the development of compact, low-cost and low-powered analytical devices. Here we report on the development of a microfluidic platform for water quality monitoring. This system has been successfully applied to in-situ monitoring of phosphate in environmental and wastewater monitoring applications. We describe a number of the technical and practical issues encountered and addressed during these deployments and summarise the current status of the technology

Modeling of GRACE-Derived Groundwater Information in the Colorado River Basin

Groundwater depletion has been one of the major challenges in recent years. Analysis of groundwater levels can be beneficial for groundwater management. The National Aeronautics and Space Administration’s twin satellite, Gravity Recovery and Climate Experiment (GRACE), serves in monitoring terrestrial water storage. Increasing freshwater demand amidst recent drought (2000–2014) posed a significant groundwater level decline within the Colorado River Basin (CRB). In the current study, a non-parametric technique was utilized to analyze historical groundwater variability. Additionally, a stochastic Autoregressive Integrated Moving Average (ARIMA) model was developed and tested to forecast the GRACE-derived groundwater anomalies within the CRB. The ARIMA model was trained with the GRACE data from January 2003 to December of 2013 and validated with GRACE data from January 2014 to December of 2016. Groundwater anomaly from January 2017 to December of 2019 was forecasted with the tested model. Autocorrelation and partial autocorrelation plots were drawn to identify and construct the seasonal ARIMA models. ARIMA order for each grid was evaluated based on Akaike’s and Bayesian information criterion. The error analysis showed the reasonable numerical accuracy of selected seasonal ARIMA models. The proposed models can be used to forecast groundwater variability for sustainable groundwater planning and management

An Aerial Gamma Ray Survey of Springfields and the Ribble Estuary in September 1992

<p>A short aerial gamma ray survey was conducted in the vicinity of the Springfields site and Ribble Estuary from 1st-5th September 1992, to define existing background radiation levels, against which any future changes can be assessed. A twin engine AS 355 "Squirrel" helicopter chartered from Dollar Helicopters was used for this work. It was loaded with a 16 litre NaI(Tl) gamma ray detector and spectroscopy system on the 31st August and during the following days over 2700 separate spectra were recorded within a survey area of 20 x 12 km. Gamma ray spectra were recorded every 5 seconds at survey speed and altitude of 120 kph and 75 m respectively. A flight line spacing of 0.3km was chosen for the main survey area. On the 3rd September a low altitude, high spatial resolution (flight line spacing 100m and altitude 30m) was made over Banks Marsh (an area frequented by local wild fowlers).</p> <p>Survey results have been stored archivally and used to map the naturally occurring radionuclides 40K, 214Bi and 208Tl together with 137Cs and total gamma ray flux. In addition, for the first time, estimates of 234mPa in terms of deconvoluted count rate (normalised to 100m altitude) were made in the presence of 228Ac interference probably in disequilibrium with its parent thorium series.</p> <p>The maps provide a clear indication of the distribution and sources of environmental radioactivity in the Ribble at the time of the survey. The Ribble estuary is subject to regular and ongoing ground based studies by BNF, MAFF, HMIP, and University based groups, as a result of the authorised discharges of low level radioactivity from the Springfields site. The results of this survey complement this ground based work, and add to confidence that the estuarine system, it's associated sediments, tide washed pastures, salt marshes and river banks, have been thoroughly examined. There is support for earlier conclusions that the Cs on the salt marshes is the dominant source of external gamma exposure, and that the Springfields contribution to these locations is minor in comparison with this, Sellafield derived, signal. Upstream the situation is more complex, particularly where the dynamic sources of beta radiation are considered. As far as critical group assessments are concerned the survey provides clear evidence that the areas affected by 137Cs, where external gamma dose and possible food chain effects are of greatest interest, are in the lower reaches of the Ribble, whereas, at the time of the survey the 234mPa distribution was in the upper reaches of the river. This not only confirms the findings of ground based work, but provides some assurance that the different exposure paths (external gamma dose, skin dose) are not entirely synergistic. The discovery of possible transient sources of natural 228Ac in the salt marsh environment as a consequence of Th series disequilibrium immediately following spring tides is extremely interesting. If substantiated by further studies using semiconductor detectors this provides a new insight into the dynamic radiation environment of tide washed contexts.</p> <p>Aerial survey can potentially provide a rapid and cost effective means of studying environmentally dynamic sources such as 234mPa. In the case of the Ribble it would be necessary to reduce survey height to below 50m ground clearance to improve spatial resolution. Possible inconvenience to residents and property owners of such low altitude flights would have to be considered in addition to the potential value of environmental knowledge of the behaviour of short lived nuclides in a dynamic system such the Ribble estuary. There is nonetheless considerable potential for time series studies of this location. Recent flight trials by SURRC incorporating high efficiency germanium semiconductor detectors have verified the feasibility and potential a hybrid scintillation⁄ semiconductor spectrometer. Such a device can resolve any ambiguities arising from overlapping gamma ray peaks. This is particularly relevant to the confirmation of 228Ac in salt marshes. Ground based sampling at the time of measurement would enable concentration calibrations to be made for these dynamic sources. Further ground based measurements would be desirable to establish the extent to which low energy photons contribute to external gamma ray dose rates from sources with pronounced subsurface activity maxima.</p&gt