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Severe flooding and excess nutrient pollution, exacerbated by heightened anthropogenic pressures (e.g., climate change, urbanization, land use change, unsustainable agricultural practices), have been detrimental to riverine systems and their estuaries. The degradation of riverine systems can negatively impact human and environmental health, as well as local, regional, and even global economies. Floods provide beneficial ecosystem services (e.g., processing pollutants, transferring nutrients and sediment, supporting biodiversity), but they can also damage infrastructure and result in the loss of human life. Meanwhile, eutrophication can cause anoxic dead zones, harming aquatic ecosystems and public health. To address the issues facing riverine systems, focus has shifted to watershed-scale management plans. However, it can prove challenging to quantify the cumulative impacts of multiple stream restoration projects within a single watershed on flooding and nutrient removal. Previous studies have quantified the effects of stream restoration on flood attenuation. However, our first study fills a substantial knowledge gap by evaluating the impacts of different floodplain restoration practices, varied by location and length, on flood attenuation and floodplain inundation dynamics at the watershed scale during more frequent storm recurrence intervals (i.e., 2-year, 1-year, 0.5-year, and monthly). We created a 1D HEC-RAS model to simulate the effects of Stage 0 restoration within a 4th-order generic watershed based on the Chesapeake Bay watershed. By varying the percent river length restored and location, we found that Stage 0 restoration, especially in 2nd-order rivers, can be particularly effective at enhancing flood attenuation and floodplain inundation locally and farther downstream. We addressed the water quality component by using a random forest machine learning approach coupled with artificial neural networks to find trends and predict nitrate removal rates associated with spatial, temporal, hydrologic, and restoration features. Our results showed that hydrologic conditions were the most important variable for predicting actual nitrate removal rates. Overall, both studies demonstrate the importance of hydrologic connectivity for flood attenuation, channel-floodplain exchange, and nutrient processing. / Maryland Department of Natural Resources; National Fish and Wildlife Foundation through the U.S. Environmental Protection Agency’s Chesapeake Bay Program Office; Chesapeake Bay Trust / Master of Science / Severe flooding and nutrient pollution from sources such as urban and agricultural runoff have been detrimental to the health of rivers. The degradation of rivers can negatively impact human and environmental health, as well as local, regional, and even global economies. Floods can be both helpful, by providing water quality benefits and supporting wildlife, and harmful, causing damage and even loss of life. Excess nutrients, such as nitrogen, can create underwater zones void of life, with serious consequences for aquatic life and public health. To address the flooding and water quality issues facing rivers, focus has shifted to landscapelevel river network management plans. However, it can prove challenging to understand the impacts of multiple stream restoration projects within a larger river network on flooding and nutrient removal. We address the flooding component by using a model to simulate the effects of different floodplain restoration techniques on a medium-sized watershed that is generally based on streams that flow into the Chesapeake Bay. Our model simulated small, relatively frequent storm events that, on average, occur every two years to once a month. By varying restoration length and location, we found that restoration practices with lower streambanks can be particularly effective at slowing down floods, reducing their overall severity by allowing more water to access the floodplains. This was especially true when restoration occurred in smaller streams, and the effects were seen both locally and farther downstream. We address the water quality component by using a different model to find patterns and predict nutrient removal rates associated with different landscape, seasonal, storm event, and restoration features. Our results showed that the most important variable for predicting nutrient removal rates was whether a stream was experiencing normal flow or stormflow conditions. Overall, both studies demonstrate the importance of restoring rivers in a manner that encourages water to flow from the channel into the floodplains during smaller storm events, because this will reduce the severity of downstream flooding while simultaneously improving water quality.

This interdisciplinary doctoral dissertation addresses land subsidence in different and diverse study cases in the world, employing advanced techniques and methodologies to measure their magnitude and comprehensively explore its causes, and implications. Investigating areas such as the San Luis Potosi metropolitan area, Alaşehir-Sarıgöl sub-basin (ASSB) in Türkiye, and the Alto Guadalentín Valley in Spain, the research unveils critical insights into the complex dynamics of subsidence phenomena. Utilizing advanced remote sensing techniques like Persistent Scatterer Interferometry (PSI) and Coherent Pixels Technique (CPT), the study assesses subsidence rates and correlates them with factors such as trace faults, groundwater extraction, and soft soil thickness. Validation methodologies were developed and proposed to the scientific community on the first stage, integrating Global Navigation Satellite System (GNSS) benchmarks, enhance the reliability of Differential Synthetic Aperture Radar Interferometry (DInSAR) measurements, ensuring a robust foundation for subsequent analyses. The research aims to contribute to the understanding of land subsidence and contribute to create a decision-support framework to mitigate the phenomenon while addressing specific research objectives within each identified topic of inquiry. The research topic 1 includes the “DInSAR for monitoring land subsidence in overexploited aquifers”. In the San Luis Potosi metropolitan area (Mexico), the application of CPT technique reveals intriguing correlations between trace faults, land subsidence, and groundwater extraction. Specifically, areas in the municipality of Soledad de Graciano Sánchez exhibit subsidence values ranging between -1.5 and -3.5 cm/year, while in San Luis Potosi, values range from -1.8 to -4.2 cm/year. The validation of CPT results against five Global Navigation Satellite System (GNSS) benchmarks establishes a robust correlation of 0.986, underlining the reliability of InSAR-derived deformations. Additionally, in regions like the Alaşehir-Sarıgöl sub-basin (Türkiye), where water stress is heightened due to intensive agricultural irrigation, the study explores the roles of tectonic activity and groundwater withdrawal in land subsidence. Utilizing the P-SBAS algorithm, 98 Sentinel-1 SAR images in ascending orbits and 123 in descending orbits were analysed, covering the period from 2016 to 2020. Independent Component Analysis was applied to distinguish long-term displacements from seasonal variations in the DInSAR time series data. Displacement rates of up to -6.40 cm/year were identified, thus, the proposed P-SBAS algorithm facilitates the monitoring of displacement, revealing direct correlations between DInSAR displacement and critical factors like aquitard layer compaction. These findings contribute valuable insights into the dynamic interactions shaping overexploited aquifers. The research topic 2, developing parallelly to topic 1, consists of the “Validation of DInSAR data applied to land subsidence areas”. Addressing the imperative for validation methodologies in subsidence assessments, a systematic approach introduces statistical analyses and classification schemes. This methodology is designed to validate and refine DInSAR data, enhancing the reliability of subsidence assessments. By normalizing Root Mean Square Error (RMSE) parameters with the range and average of in-situ deformation values and employing the squared Pearson correlation coefficient (R²), a classification scheme is established. This scheme facilitates the acceptance/rejection of DInSAR data for further analyses through the application of automatic analysis supported by a Matlab © code, ensuring a more accurate representation of land subsidence phenomena. The research topic 3 covers the exploitation of DInSAR data for assessing flooding potential and determining characteristic parameters of aquifer systems. The first one is “Impact of land subsidence on flood patterns”. The study in the Alto Guadalentín Valley, a region experiencing extreme flash floods jointly with high-magnitude land subsidence, integrates flood event models, Differential interferometric SAR (DInSAR) techniques, and 2D hydraulic flow models. Through Synthetic Aperture Radar (SAR) satellite images and DInSAR, land subsidence's magnitude and spatial distribution are quantified. The results demonstrate significant changes in water surface elevation between the two 1992 and 2016 temporal scenarios, leading to a 2.04 km² increase in areas with water depths exceeding 0.7 m. These outcomes, incorporated into a flood risk map and economic flood risk assessment, underscore the pivotal role of land subsidence in determining inundation risk and its socio-economical implications. The research offers a valuable framework for enhancing flood modelling by considering the intricate dynamics of land subsidence. The second application of DInSAR data is about the “Automatic calculation of skeletal storage coefficients in aquifer systems”. In response to the need for automating data analysis for specific storage coefficients in aquifer systems, a MATLAB© application is introduced. This application streamlines the correlation between piezometric levels and ground deformation, significantly reducing analysis time and mitigating potential human interpretation errors. The developed application integrates temporal groundwater level series from observation wells and ground deformation data measured by in-situ or remote sensing techniques (e.g., DInSAR). Through the automatic construction of stress-strain curves, the application contributes to the estimation of skeletal storage coefficients, offering a valuable tool for evaluating aquifer system behaviours. This comprehensive research, guided by the complexities of these three distinct research topics, yields detailed insights and methodological advancements. By integrating diverse datasets and employing advanced techniques, this dissertation offers a multidimensional understanding of land subsidence dynamics and provides a robust foundation for sustainable groundwater management globally. / This research is funded by the PRIMA Programme supported by the European Union (Grant agreement 1924), project RESERVOIR.

This thesis deals with examining the possibility of revitalizing the watercourse Osoblaha. It flows through the cadastral territories of municipalities Bohušov, Osoblaha and Kašnice u Bohušova. In this thesis there will be proposed a measure to increase biodiversity of the flow. The trough will be loosened in appropriate segments, oxbow lakes and ponds will be designed. Also the bank shelters for fish stock will be suggested. For slope stabilization will be used reinforcement of fresh willow fences. Impermeable shoots or disintegrating oxbow lakes will be projected in the straight sections of the flow.

The diploma thesis deals with the proposal of measures on the Svratka stream in the cadastral area Český Herálec and Herálec na Moravě. The aim of the diploma thesis is to propose appropriate flood protection in the Herálec urban area and to elaborate proposals of nature friendly measures outside the municipality’s built up area, which will enable the renewal of the ecological functions of Svratka in the spring area. In the diploma thesis the assessment of the current state of the watercourse in the analyzed locality was caried out and also the assessment of the capacity of the watercourse and the objects on there. Furthermore, the flood levels and its areas were determined. Hydraulic water flow calculations were performed using the 1D and 1D/2D numerical model. For calculation, HEC-RAS 5.0.3 was used. When processing a 1D/2D numerical model, a manual describing the progress of work in the HEC-RAS 5.0.3 program was also created. On the basis of the results from the numerical model, a proposal for flood protection measures in the urban area and nature friendly measures in the extravilan was carried out.

The aim of the diploma thesis is to describe and evaluate in detail the current state of the Bobrava river in the interest section – river kilometer 1,832-5,743. Part of the work is to assess the capacity of the river flow and the objects connected with it and find the class of an actual safety at village Zelesice. The calculation of the flow rate is performed by using the 1D mathematical model HEC-RAS for selected N-year flows. On the basis of the results of the flow rate, it is made the idea of natural freindly flood protection before the value of the 20-year flow. The result is two variants of river basin adjustment, when each one is leading to make Zelesice safer place and to improve the current state of the river Bobrava.

Diploma´s thesis solve flood protection study of Janova (region Vsetín). Model of flow was created based on geometry of the watercourse and hydrological data of Vsetinska Becva on the municipality. Model of flow was created using HEC-RAS 4.1. Calculation results of centenarian maximum peak discharge were base for design measures, which were the necessary for improvement flood protection of area.

My diploma thesis deals with the issue revitalization of a small stream. Assessment and design of revitalization is done on Kuřimka stream which flows through the cadastral territory of the Moravian Knínice - Chudčice - Kníničky. In the diploma thesis were designed several of revitalization measures: stabilization of longitudinal tilt with the use of stone steps in the bottom and wooden thresholds, sedimentation reservoir for capturing sediment and slope stabilization using willow fences and gabions. Proposal of revitalization measures does not deteriorate runoff conditions.

Determination of immeasurable parameter, the Manning’s roughness coefficient, is a complex problem of open channel hydraulics for more than 200 years. Now it doesn’t exists a method for determining an exact value of 1D roughness coefficient for computation water levels in watercourses. Doctoral thesis is focused for comparing different approaches to determine a roughness coefficient, especially for empirical equations. It were sought empirical equations, which are suitable for wide spectrum of water stages, types of bed material, channel shapes and channel dimensions. Selected equations were sorted on the base of two methods by the best values of medians and standard deviations of measured and computed values of roughness coefficients. Furthermore, it were compared qualities of roughness coefficient determination by tables, by photographic catalogs, CES software and by Cowan’s method, which has been extended and recalibrated. The computed values of roughness coefficients by those four methods were compared with values from own measurements in 27 locations in watercourses near of Brno and Frýdek-Místek. Also it were compared the grain size curves determined by sieving, by Wolman’s method and by Subjective estimation. Doctoral thesis is marginally focused for beginning of sediment movement, roughness coefficient of bedforms (dunes), grass and trees.

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