This research focuses on estimation and analysis of stream sinuosity using GIS. Fifty-five streams including 13 streams of order 0, 17 streams of order 1, 15 streams of order 2 and 10 streams of order 3 in Virginia were considered. Several GIS datasets from various sources, including the Virginia Base Mapping Program (VBMP) and United States Geological Survey (USGS), were used to generate stream networks using GIS. Sinuosity was computed using GIS based on a technique comparable to the approach used in an Environmental Monitoring and Assessment Program's (EMAP's) field survey report. Field sinuosity data from EMAP report were used as reference data for analyzing the accuracy of sinuosity values from different GIS data sources and resolutions. The GIS technique was implemented for computing sinuosity for 55 streams in Virginia using vector data including the VBMP Hydro44 and National Hydrography Data (NHD). Insufficient statistical evidence was found to support the hypothesis that the computed sinuosity values using Hydro44 and NHD data are different from EMAP field data for all 55 streams. Sinuosity values computed using Hydro44 and NHD were found to increase with the increase in EMAP sinuosity (positive correlation) for all 55 streams. EMAP data on sinuosity, however, did not predict sinuosity values computed using Hydro44 (R² = 27%) and NHD (R² = 10%) sources well. It was found that the GIS technique of computing sinuosity using digital data such as Hydro44 (VBMP source) and NHD (USGS source 1:24,000) is better suited for stream orders 2 and 3. Insufficient statistical evidence was found that computed sinuosity values for streams derived using various resolutions (i.e., DTM 3m, DTM 10m, DTM 30m, DEM 10m and DEM 30m) are different from EMAP field data. Positive correlation was observed between sinuosity values for streams derived in all resolutions with EMAP field data. DTM 10m resolution data yielded best correlation value (75%) with EMAP field data. / Master of Science

<p>Eutrophication from agricultural runoff is a global issue, and can often result in degradation and loss of aquatic habitat. The overall objective of this study is to gain a better understanding of the factors that influence variation in water chemistry of low-order streams in an agricultural watershed. The first chapter finds significant differences between the effects of livestock- vs and crop-based operations on water chemistry while modeling the relationship between independent landscape variables and major water-quality parameters in an agroecosystem. I also determine significant differences exist in dependent variables among seasons and are best described by the agriculturally relevant calendar (ARC). In Chapter 2, I compared the effectiveness of discrete and continuous sampling programs for monitoring the impacts of cattle disturbances on water quality. I found that daily total phosphorus (TP) concentrations (integrated sample taken every 6 hours) were not significantly correlated with precipitation and were significantly lower than discrete water samples. Turbidity readings (recorded every half hour) showed spikes that corresponded with cattle hydration events and increased levels of nutrients through backwash. . In Chapter 3, I find a significant relationship between periphyton growth and the level of primary nutrients (TP, soluble reactive phosphorus, total-ammonia nitrogen). Thus, for low-order streams influenced by small family farms, acrylic rods may be an inexpensive indicator of excess limiting nutrients. In such environments stream length may be a stronger measure of streams than stream order since total nitrogen, TP and pH were significantly correlated with stream length.</p> / Master of Science (MSc)

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-09-20T18:27:17Z No. of bitstreams: 1 marciomalafaiafilho.pdf: 3174349 bytes, checksum: be5afdfc53cbb28cf2e49c0dcae4ca22 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-09-22T15:19:40Z (GMT) No. of bitstreams: 1 marciomalafaiafilho.pdf: 3174349 bytes, checksum: be5afdfc53cbb28cf2e49c0dcae4ca22 (MD5) / Made available in DSpace on 2017-09-22T15:19:40Z (GMT). No. of bitstreams: 1 marciomalafaiafilho.pdf: 3174349 bytes, checksum: be5afdfc53cbb28cf2e49c0dcae4ca22 (MD5) Previous issue date: 2013-05-29 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A água tem fundamental importância para a vida na Terra. Cerca de 70% da superfície terrestre é coberta por água, sendo que a maior parte dela pelos oceanos. Do total das águas, 3,46% encontram-se nos continentes. Todavia, os números sobre a área da superfície aquática continental no planeta são muito variáveis, pois geralmente negligenciam a superfície total dos corpos d’água de menores dimensões. Portanto, este estudo estimar o comprimento da rede hidrográfica brasileira, bem como sua distribuição sobre as 12 Regiões Hidrográficas do Brasil, através do uso do Shuttle Radar Topographic Mission (SRTM) e de técnicas de geoprocessamento apoiadas nos Sistemas de Informações Geográficas (SIG). Além do comprimento, estimado em 7.325.672 Km – correspondente à soma de todos os rios do território brasileiro, discriminaram-se as ordens dos rios segundo a metodologia proposta por Strahler, metodologia esta que busca uma hierarquização dos córregos e rios. Nesta discriminação observou-se que os rios de primeira ordem (os que se comunicam diretamente com as nascentes) representam 51% do comprimento total dos rios e córregos em território nacional, indicando que os menores rios são mais abundantes que os rios maiores. / It is well-established that water has a crucial importance to life on Earth. Nearly 70% of the Earth surface is covered by water, being the greatest part of it covered by the oceans. Out of all the water on Earth, 3.46% can be found in continents. However, the numbers concerning the continental water surface of the planet are changeable, once researchers generally do not consider the total surface of smaller water bodies. Therefore, this study aims at estimating the length of the Brazilian hydrographic network, as well as its distribution over 12 Brazilian hydrographic regions, by means of the Shuttle Radar Topographic Mission (SRTM). The study included geoprocessing techniques supported by the Geographic Information Systems (GIS). In addition to an estimated length of 7,325,672 km – correspondent to the sum of all the Brazilian rivers, this work also discriminated the stream order, as proposed by Strahler’s methodology, which casts about for the hierarchy of both rivers and streams. Through this discrimination, it was observed that first order rivers (those which communicate directly with their source) represent 51% of the total length of the rivers and streams inside the Brazilian territory, thus indicating that small rivers are most abundant than large ones.

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