The growing human population threatens the many of the earth’s biological systems. In the last 600 years extinction rates risen from 1 extinction per million species per year (E/MSY) in the 1400’s to 50 E/MSY today. During this time period 1.5% of all known birds have gone extinct, because they could not adapt quickly enough to human mediated changes. The goal of this dissertation was to determine how urbanization and anthropogenic services needed to support urban areas impact cypress dome wetland aquatic insect and migratory bird populations that depend on them. In Central Florida cypress dome hydroperiods are driven by seasonal rainfall conditions and fill June and July with the onset of the Florida rainy season then begin drying beginning in October with the onset of the dry season. Some wetlands were strongly influenced by groundwater pumping and dried out quicker than others, a characteristic that reduced annual insect emergence. Decreased adult insect populations were associated with lower emergence rates early in the dry season led to lower utilization by insectivorous birds. Winter migratory birds significantly related with adult insect abundance during winter months (r = 0.578, p=0.049), and utilized this region at the peak in adult insect populations. Conversely, Neotropical migrants travel through the region during spring when insects are scarce, and adult insects began sharp decline suggesting that Neotropical migrants depleted populations possibly leading to interspecies competition. Neotropical migrants strongly avoided urban areas and declined by 70% in urban areas, which may contribute to declining Neotropical migratory bird populations as a lack in adequate stopover sites may limit entire species. If they are not able to adapt foraging patterns that utilize urban areas in Central Florida where urban development is increasing rabidly populations may continue to decline.

In this research, the fundamental mechanics for the changes in stresses and strains states due to groundwater pumping is formulated. This was accomplished by developing a 3D closed form solution. The results from this research are compared with results of finite element (FE) analyses and data obtained from interferometric synthetic aperture radar (InSAR). Land subsidence (LS) due to groundwater pumping from a single well for different geological profiles and the reason why LS continues after groundwater pumping cessation were investigated. FE analyses for four different scenarios were used to investigate the effects of cemented layers and non-cemented layers above the aquifer on EF initiation. A practical method which is based on the stiffness and cementation strength of the cemented layer and the gradient of the slope of the subsidence bowl (ɑ) was proposed to determine earth fissure (EF) initiation. Three-point bending beam test was conducted in the lab to determine the mode of failure and the modulus of rupture of a local cemented soil that occurs in areas where EFs were observed. The major findings are as follows. LS due to groundwater pumping consists of i) isotropic compression and ii) simple shear on vertical planes with rotation. For a parabolic distribution of groundwater level in a homogenous aquifer, simple shear on vertical planes will be dominant when the characteristic length of the aquifer is larger than √2 times the aquifer thickness. Fine-grained soils are responsible for LS occurring after the cessation of pumping and for sagging in LS profiles. Regardless of the stiffness and cementation strength of the top layer above the aquifer, EF will not initiate if ɑ is less than 8x10⁻⁵. When the stiffness of the top cemented layer increases, it becomes more prone to EF initiation. However if the layer is stiff enough to be classified as "rock" then a higher value of ɑ is needed to initiate an EF. The experiments show that the preferred mode of failure of a cemented soil is shear rather than bending and existing cracks significantly influence the results of EF formation.

No description available.

The main objective of this dissertation was to investigate the impacts of human activities and climate control on hydrologic responses using the Integrated Hydrologic Model (IHM), which dynamically couples HSPF and MODFLOW. The study first evaluated the impacts of land use change and rainfall variability on hydrologic responses—such as streamflow, evapotranspiration (ET), groundwater ET, recharge, and groundwater heads—in the Anclote River basin (ARB), Florida. The results provided insights into the uncertainties in hydrologic responses due to rainfall variability. Secondly, hydrologic response flux changes were partitioned into anthropogenic causes, including groundwater pumping, irrigation, and land use change, by the IHM in the Trout Creek Watershed, Florida. Hydrologic response flux changes per unit of human stress flux change were calculated and assessed at mean annual and monthly scales, offering insights for projecting hydrologic changes due to anthropogenic stressors. For climate control, a three-stage precipitation partitioning framework was proposed to study climate impacts on mean annual groundwater ET across 33 gauged watersheds in west-central Florida using the IHM. The roles of groundwater ET in long-term water balance were quantified through four ratios, and the contributions of various climate variabilities to groundwater ET were determined, providing new insights into sustainable groundwater management. Moreover, the dissertation explored the development and application of a multi-scale framework for the IHM, enhancing simulation accuracy and efficiency across different spatial scales and facilitating better water resource management. Applied to the ARB, this framework demonstrated improved model performance in capturing hydrologic changes due to local human activities and climate variability. This research underscored the significance of integrated surface-groundwater models in accurately assessing hydrologic impacts for water resource management, especially in regions with shallow water tables. It advanced the understanding of human and climate impacts on hydrologic systems, offering valuable tools and methodologies for integrated water resource management.