This study examines the relationship between land use and temperature change in Dallas County, TX. The purpose of this research is to analyze the relationship between temperature and land use and to identify the primary factors contributing to the formation of urban heat islands based on different categories of land use. Specifically, this research analyzes the elements that contribute to the urban heat island effect in Dallas County using temperature data provided by remote sensing imagery and parcel-based land use data using Geographic Information System (GIS) technique and a correlation analysis method, which was employed to analyze the relationship between temperature and land use. The results of this study showed that every land use category has different temperature averages and those patterns were observed similarly in both 2000 and 2005. Parking, airport, commercial, industrial, and residential areas have relatively high temperatures. In contrast, water, undeveloped area and parks showed relatively low temperatures. Another major finding was ratio of land use composition affected the temperature of census tracts. Correlation analyses of land use and temperature in 2000 and 2005 indicate that various types of land use categories have significant relationships with temperature. Among them commercial, industrial, residential, parking, and infrastructure, are positively associated with temperature, while undeveloped, parks, water, and dedicated areas are negatively associated with temperature. Areas with a high ratio of commercial use showed the highest and undeveloped areas showed the lowest relationship. Furthermore, through the analysis of the relationship between land use and temperature change for five years (2000-2005), this study finds that temperature change depends on the ratio of each land use category change. The results of this study can help local planning and policy decisions which are related to urban land use planning concerning temperature change such as zoning, environmental regulations and open space preservation.

Developing countries have been rapidly urbanising over the last decades, resulting in major environmental pressures and increased vulnerability to natural disasters. A complex combination of factors, including climate change, land use change, poorly implemented regulation and a lack of integrated planning has often resulted in environmental degradation and disproportionate impacts of natural disasters affecting millions worldwide, particularly in tropical cities. The main aim of this study is to understand the effects of land-use and climate change on flooding in the Greater Port-Harcourt watershed. The specific research objectives were: to understand the historical and future land use /land cover changes; to understand the magnitude of change in hydrologic and hydraulic conditions due to land-use and climate changes; to assess the influence of different forest mitigation scenarios on peak-discharge; and to make recommendations on how to improve future planning using insights from this study. Methodologically, the post-classification change detection method was applied to examine the extent and nature of historical LULC changes using remotely sensed data. Future LULC changes were estimated by superimposing the 2060 digitised Masterplan map on the year 2003 baseline imagery. Hydrologic changes were assessed using HEC-HMS model, while changes in the hydraulic condition were assessed using HEC-RAS model. Model output was further used to map flood hazards, flood zones and damage potential. Priority areas and infrastructure at risk were identified by means of their location in flood zones and exposure to floods with high damage potential. On the extent of change, this study revealed that urbanisation and loss of agricultural land had been the dominant and intensive land use change in the watershed. Urbanisation is projected to almost double its 2003 extent by 2060 and is likely to remain the dominant force of land use change. On the nature of change, this study found that urban land was the most dynamic in terms of gross gain and net change. It exhibited the grossest gain (about 9% of the watershed) and the grossest loss leading to a high net change of about 8.6%. In fact, the most prominent transition was the conversion of agricultural land (about 422km2) to urban land, and roughly 93.3% of all conversions to urban land resulted from agricultural land. On the process of change, urban land mainly experienced a net-type of change (change in quantity), whereas changes in agricultural land was more of a swap-type of change (change in location). Importantly, the study reveals that the impact on flood flow was historically significant (about 68%) and is projected to amplify in future, however, these changes are largely attributed to increased storm size. Urbanisation is likely to have little or no impact on annual maximum peak flow at the watershed scale; however, urbanisation is projected to have a considerable impact on peak flow in a number of subbasins, which could have severe implications for flash flooding in those subbasins. Similarly, afforestation could have little or no impact on future maximum peak flow when assessed at the watershed scale. Although some subbasins experienced changes in peak flow, the effect of forest is variable. The study concludes that although the impact of urbanisation is projected to be insignificant at the watershed scale, it could also increase flood risk due to increasing developments in floodplains and channel encroachment. Priority infrastructure and areas requiring urgent flood risk management include the Port-Harcourt seaports, Onne seaport, the University of Science and Technology and cement factory. Priority areas in the Masterplan are mainly in the south (Phase 3), comprising of the Air force base and the residential area near Onne seaport. Lastly, approximately 8.1km and 189m of road and rail network are at greater risk of flooding by means of their exposure to floods with the highest damage potential. Based on this study, I have furthered understanding by showing that the transition to urban land category was dominated by net changes (i.e. changes in quantity). I have also furthered understanding by showing that substantial changes in future urban land-use may not have significant effect on flood parameters. My main contribution to knowledge is that despite the high rate of urbanisation in the GPH watershed and its minimal impact on flooding (which could be due the large size of the storm and watershed), urbanisation could still increase flood risk due to greater exposure of elements at risk in the flood plains to damaging floods. Based on the results, the study recommends that the development authorities should integrate both structural measures (mainly for flood defence around existing developments) and non-structural measures (primarily for future developments). For flood risk management research, this study recommends that conclusions about the effects of urbanisation should not be made solely on the basis of changes in hydrology and river hydraulics, however researchers should also consider the exposure of important elements at risk within the floodplains under study to better understand the effects of urbanisation. Moreover, to better understand urbanisation effects on runoff dynamics in other watersheds, this study recommends that research efforts should be concerted in understanding subbasin-scale changes given that the effects of urbanisation are more pronounced in smaller basins.

Thecamoebian tests from recent lacustrine sediments have been shown to be a useful proxy to study environmental changes such as land-use changes, pollution, and climate shifts. In this study, the usefulness of thecamoebians as an environmental proxy for the Middle Mississippi River (MMR) floodplain is explored. Sediment cores and surface samples were collected from two sites in Alexander County, IL: Southern Illinois University's (SIU) MMR Wetland Field Station near East Cape Girardeau, IL and Horseshoe Lake, a dammed oxbow managed by the IL Department of Natural Resources (DNR), near Olive Branch, IL. These sites represent different floodplain environments, management histories, and flooding patterns. The thecamoebian populations were expected to reflect these differences while also responding to regional signals associated with development, agriculture, and climate. Cores were subsampled at a 5cm interval and all samples were sieved with 150μm and 45μm screens to retain thecamoebian tests. Sieved sediment was examined under a microscope and at least 100 tests were identified in each sample. Pre- and post-land clearing assemblages are recognized at each site, primarily by the increased abundance of the eutrophic-indicating species Cucurbitella tricuspis. Additionally, grab samples collected from the wetlands site during the spring indicate that the site may be influenced by road salt runoff in addition to agricultural activity. These results suggest that thecamoebians are a useful land-use change proxy and more research is needed to better understand the environmental conditions influencing assemblages.

Increasingly erratic flow in the upper reaches of the Mara River, has directed attention to land use change as the major cause of this problem. The semi-distributed hydrological model SWAT and Landsat imagery were utilized in order to 1) map existing land use practices, 2) determine the impacts of land use change on water flux; and 3) determine the impacts of climate change scenarios on the water flux of the upper Mara River. This study found that land use change scenarios resulted in more erratic discharge while climate change scenarios had a more predictable impact on the discharge and water balance components. The model results showed the flow was more sensitive to the rainfall changes than land use changes but land use changes reduce dry season flows which is a major problem in the basin. Deforestation increased the peak flows which translated to increased sediment loading in the Mara River.

The impact of anthropogenic activities on environment, especially the effect of land-use and climate changes was investigated in a series of studies. A comprehensive study of 16 research sites in different parts of Sweden was evaluated by using one dimensional hydrological model (CoupModel) to represent water and heat dynamics in layered soil profile covered with vegetation. Simulations are based on daily values and the results are representatives of variations in daily values and changes over years. The models accuracies controlled by measured run-off and snow depth values. However, there are uncertainties in both input data and simulated parameters. The interaction between run-off and snow depth were obtained when the models constrained by both run-off and snow depth. Parameters values variations and models performances changes in different time domains indicate the changes in land-use and climate over time and the model ability to handle these changes respectively. The strong interaction between meteorological stations density and models performances were indicated by comparing results with interpolation radius used for input data preparation.

Thesis advisor: Noah Snyder / The purpose of this study is to quantify land use change in two coastal New England watersheds using lake core analysis, orthorectified historic aerial imagery, and data from the National Land Cover Database (NCLD). The study covers Sennebec and Medomak ponds in coastal Maine, which lie between the Penobscot Bay and the southern stretch of the Kennebec River. With lake cores recording >800 years (Sennebec) and >1600 years (Medomak), the timeframe of this study spans from the era of Indigenous populations, through the period of EuroAmerican settlement, and into the modern day, to provide insight into the interactions between humans and watershed dynamics through time. / Thesis (BS) — Boston College, 2021. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Departmental Honors. / Discipline: Earth and Environmental Sciences.

Biodiversity is declining across the globe, and human-driven climate change and land-use change are among the primary drivers of this loss. Understanding the mechanisms causing declines is critical for developing effective conservation and management strategies which will not only slow biodiversity loss, but reverse it. This is relevant for virtually all species on the planet, but given the ecosystem services that they provide, pollinators are an especially important group in which to study this. Among the wild pollinators native to North America and Europe, bumblebees (Bombus) are a particularly important and beautiful group. In this thesis, I identify how climate change and land-use change interact to influence population and community change in North American and European bumblebees, and I explore the potential role of protected areas in mitigating declines. I find that climate change has increased local extinction risk for bumblebees by exposing them to temperatures beyond their historic tolerances, and I introduce a broadly applicable method which improves prediction of this climate change-related risk (Chapter 2). Examining the interactions between climate change and land-use change shows that the risk from increasing temperatures and temperature extremes is worse in historically degraded areas, and that climate change and land-use change may be driving biotic homogenization in bumblebee communities. Yet, landscape-scale patterns suggest that human land-use can be managed to have minimal, or even positive, effects on pollinators (Chapter 3). In the face of these global pressures, protected areas represent one way to conserve species. I find that increasing the amount of protected area in a region, regardless of size or management category of the protected areas, is related to reduced local extinction risk for bumblebees across North America and Europe. This benefit is especially strong in areas with high human land-use, highlighting the importance of protected areas in highly human-dominated landscapes (Chapter 4). The work within my thesis improves our understanding of how climate change and land-use change drive shifts in species and communities, and can inform on the effectiveness of specific conservation actions from gardens and urban greenspaces, to Other Effective Area-Based Conservation Measures (Chapter 5).

This study used the Soil and Water Assessment Tool (SWAT) to model 2 watersheds in Mississippi, which are the Lower Pearl River Watershed (LPRW) and the Big Sunflower River Watershed (BSRW), to simulate streamflow, groundwater storage and recharge, sediments, nutrients, and bacteria transport. The LPRW model was calibrated and validated for daily streamflow at 4 locations with R2 ranging from 0.49 to .90 and Nash-Sutcliffe Efficiency (NSE) ranging from 0.49 to 0.84. In the BSRW, the model showed good to very good performance for daily streamflow simulation (R2 = 0.53-0.75 and NSE = 0.49-0.72) and seasonal groundwater table depth fluctuations (R2 = 0.76 to 0.86 and NSE = 0.71-0.79). The BSRW model was also calibrated and validated for total sediment (TS) load (R2 = 0.50-0.72, NSE = 0.47-0.66), total phosphorus (TP) load (R2 = 0.79-0.82, NSE = 0.73-0.77), and fecal coliform bacteria concentrations (R2 = 0.56-0.60 and NSE = 0.23-0.40). In the LPRW, the effectiveness of grassed waterways, detention ponds, and parallel terraces Best Management Practices (BMPs) to attenuate peak streamflow decreases significantly under increased rainfall and under increased CO2 concentration climate change scenarios; however, under increased temperature or decreased rainfall, the effectiveness of BMPs to reduce peak streamflows did not significantly change. In the BSRW, implementing crop rotations practices with rice resulted in the lowest groundwater storage (-10.7%), but it also led to the highest increases in monthly groundwater recharge (up to +60.1%). The crop rotations with corn and cotton usually resulted in the largest increases in groundwater storage (up to +27.2%). The BSRW was modeled to assess the sensitivity of bacteria concentrations to climate change, and this study determined that bacteria concentrations were most sensitive to rainfall, followed by temperature, solar radiation, and CO2 concentrations. The BSRW model also showed significant parameter uncertainty in the streamflow, TS load, TP load, and total nitrogen (TN) load simulations, and that equifinal parameter sets exist in the model. Moreover, the SWAT parameters that were sensitive to streamflow were also found to be sensitive to sediment and nutrient transport.

Thesis advisor: Noah P. Snyder / Nitrogen is an important component in the biogeochemical processes of freshwater systems. Likewise, it is unknown if, and to what magnitude, changes in land use in the watersheds of New England lakes have affected nitrogen availability. This study examines the effects of land-use change on the present and historic isotopic signatures of nitrogen in three New England lakes of varied histories, Lower South Branch Pond, Little Kennebago Lake, and Sennebec Pond. The histories of all three sites indicate minimal discernible disturbance before the onset of Euro-American-induced land use change. For two sites, the dominant mechanism of change was timber harvest, which began in the latter half of the 19th century. Sediment cores for each site were examined and variations in geochemical and sedimentological indicators were evaluated in the context of changes within respective basins. Statistical analysis indicates significant shifts in the means and variance of the geochemistry within the Little Kennebago Lake and Sennebec Pond watersheds after the incursion of Euro-American settlers, while the Lower South Branch Pond watershed displays similarities to a more widespread signal of anthropogenic nitrogen that has been deposited remotely. The record of magnetic susceptibility in Little Kennebago Lake displays the largest variation compared to the other two lakes, which may indicate that the magnitude of land-use change within the basin was more impactful relative to Lower South Branch Pond and Sennebec Pond. This is significant in that all three sites experienced some level of land-clearance. / Thesis (MS) — Boston College, 2023. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

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