927 resultados para headwater streams


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Two sections of the Yellow River have been named to the State of Iowa’s 303d list of impaired waters. The listing reflects streams with pollution problems linked to habitat alterations, in addition to those with potential disease causing bacteria, viruses and parasites. This fact, combined with local knowledge of water quality problems, shows the need for land treatment practices and habitat improvement measures. This project would target the Yellow River watershed, which totals approximately 49,800 acres. Areas that drain directly into the Yellow River mainstream will be targeted. Individually, these areas are too small to be considered sub-watersheds. This project will assess the drainage areas for active gullies and prioritize grade stabilization structures based upon severity and impact on the fishery. Funding would be utilized to target high priority grade stabilization structure sites and provide cost-share for those projects. A prerequisite for cost-share allocation is 75% of the land contributing to the drainage area must have some form of treatment in place. The Allamakee SWCD has received an EPA Region 7 Grant toward grade stabilization structures in the same area. Landowners have indicated that 75% cost-share is necessary to implement practices. To meet this request, the EPA funding would be used at a 15% cost-share rate if matched with 60% cost-share from WIRB funding. If matched with Federal EQIP funds, 25% of funds obtained from WIRB would be used. If other funds were depleted, WIRB funds would be utilized for the entire 75% cost-share.

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An overall effort has been initiated to improve the quality of the Yellow River in Northeast Iowa by reducing the amount of sediment and bacteria entering the stream. Funding for this project will be utilized to improve stream quality to the level of fully supporting game fish such as brown, rainbow and brook trout, walleye, northern pike and smallmouth bass. The Yellow River has the potential to be one of the top trout streams, not only in Iowa, but in the entire Upper Midwest. This project will greatly enhance recreational activities such as fishing, canoeing and inner tubing and will greatly increase tourism dollars to the state. The project will specifically address two sources of impairment: stream bank erosion and coliform bacteria from both livestock and inadequate human septic systems.

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Summary of Project AWARE on the Wapsipinicon River in 2015.Project AWARE is a volunteer river cleanup event.

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The information presented in this summary document has been based on the comprehensive,"Task Force Report on Water-Oriented Outdoor Recreation, Fish and Wildlife." The overriding principle the main task force report conveyed is that Iowa should not forsake the remaining water-oriented fish and wildlife resource base in the name of economic development.The reader should refer to the task force document for more detailed information.

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A snapshot of water resource trends prepared by the Iowa DNR in collaboration with the Iowa Department of Agriculture and Land Stewardship, the U.S. Geological Survey, and The Iowa Homeland Security and Emergency Management Department.

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A snapshot of water resource trends prepared by the Iowa DNR in collaboration with the Iowa Department of Agriculture and Land Stewardship, the U.S. Geological Survey, and The Iowa Homeland Security and Emergency Management Department.

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A snapshot of water resource trends prepared by the Iowa DNR in collaboration with the Iowa Department of Agriculture and Land Stewardship, the U.S. Geological Survey, and The Iowa Homeland Security and Emergency Management Department.

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The information presented in this summary document has been based on the comprehensive, "Task Force Report on Water Resource Availability", prepared by the Iowa Geological Survey and filed with the Iowa Natural Resources Council. The reader should refer to the task force document for more detailed information.

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Benthic macroinvertebrate assemblages do not appear to differ as markedly between coldwater and warmwater streams (in Iowa, at least) as do fish assemblages, and to our knowledge no parallel evaluation of benthic macroinvertebrate communities in coldwater streams has been conducted. What is known is that many taxa are exclusively collected in coldwater environments and are considered “rare” in Iowa from a biogeographical perspective. While the warmwater BMIBI has generally proven to work well as a diagnostic tool for Iowa’s streams, the streams of Iowa’s Paleozoic Plateau tend to group in the “excellent” to “good” qualitative rating categories. The streams of this area tend to be more ecologically intact than other areas of the state; however, there are some artifacts of the current warmwater BMIBI (most specifically metric scoring related to watershed size) that skew IBI values higher. Our objective is to develop a Coldwater Benthic Index (CBI) which will provide a more accurate assessment of streams classified, or potentially classifiable, as coldwater.

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Iowa Natural Resources Council's Water Plan 78, the main report of the State Water Plan Framework Study. This report is the culmination of the three-year cooperative effort between this agency and the Department of Environmental Quality, Conservation Commission, Department of Soil Conservation, and the Geological Survey, funded by the Legislature in 1978.

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The 1985 State Water Plan was prepared by the Department of Water, Air and Waste Management in response to a 1982 legislative mandate. The report contains recommendations for conservation, priority allocation system, mechanisms to define shortage and initiate the allocation system, better define beneficial use and improving daily management of water rights, well interference and compensation, and groundwater protection strategy.

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In anticipation of regulation involving numeric turbidity limit at highway construction sites, research was done into the most appropriate, affordable methods for surface water monitoring. Measuring sediment concentration in streams may be conducted a number of ways. As part of a project funded by the Iowa Department of Transportation, several testing methods were explored to determine the most affordable, appropriate methods for data collection both in the field and in the lab. The primary purpose of the research was to determine the exchangeability of the acrylic transparency tube for water clarity analysis as compared to the turbidimeter.

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The Iowa Department of Public Health (IDPH), Division of Environmental Health, Health Assessment Program gives people information about harmful chemicals and organisms in their environment. Blue-green algae are microscopic organisms that are naturally present in lakes and streams. Some blue-green algae produce toxins that could pose a health risk to people and animals when they are exposed to them in large enough quantities. This fact sheet answers questions about blue-green algae.

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The symbol transition density in a digitally modulated signal affects the performance of practical synchronization schemes designed for timing recovery. This paper focuses on the derivation of simple performance limits for the estimation of the time delay of a noisy linearly modulated signal in the presence of various degrees of symbol correlation produced by the varioustransition densities in the symbol streams. The paper develops high- and low-signal-to-noise ratio (SNR) approximations of the so-called (Gaussian) unconditional Cramér–Rao bound (UCRB),as well as general expressions that are applicable in all ranges of SNR. The derived bounds are valid only for the class of quadratic, non-data-aided (NDA) timing recovery schemes. To illustrate the validity of the derived bounds, they are compared with the actual performance achieved by some well-known quadratic NDA timing recovery schemes. The impact of the symbol transitiondensity on the classical threshold effect present in NDA timing recovery schemes is also analyzed. Previous work on performancebounds for timing recovery from various authors is generalized and unified in this contribution.

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Abstract: To understand the processes of evolution, biologists are interested in the ability of a population to respond to natural or artificial selection. The amount of genetic variation is often viewed as the main factor allowing a species to answer to selection. Many theories have thus focused on the maintenance of genetic variability. Ecologists and population geneticists have long-suspected that the structure of the environment is connected to the maintenance of diversity. Theorists have shown that diversity can be permanently and stably maintained in temporal and spatial varying environment in certain conditions. Moreover, varying environments have been also theoretically demonstrated to cause the evolution of divergent life history strategies in the different niches constituting the environment. Although there is a huge number of theoretical studies selection and on life history evolution in heterogeneous environments, there is a clear lack of empirical studies. The purpose of this thesis was to. empirically study the evolutionary consequences of a heterogeneous environment in a freshwater snail Galba truncatula. Indeed, G. truncatula lives in two habitat types according the water availability. First, it can be found in streams or ponds which never completely dry out: a permanent habitat. Second, G. truncatula can be found in pools that freeze during winter and dry during summer: a temporary habitat. Using a common garden approach, we empirically demonstrated local adaptation of G. truncatula to temporary and permanent habitats. We used at first a comparison of molecular (FST) vs. quantitative (QST) genetic differentiation between temporary and permanent habitats. To confirm the pattern QST> FST between habitats suggesting local adaptation, we then tested the desiccation resistance of individuals from temporary and permanent habitats. This study confirmed that drought resistance seemed to be the main factor selected between habitats, and life history traits linked to the desiccation resistance were thus found divergent between habitats. However, despite this evidence of selection acting on mean values of traits between habitats, drift was suggested to be the main factor responsible of variation in variances-covariances between populations. At last, we found life history traits variation of individuals in a heterogeneous environment varying in parasite prevalence. This thesis empirically demonstrated the importance of heterogeneous environments in local adaptation and life history evolution and suggested that more experimental studies are needed to investigate this topic. Résumé: Les biologistes se sont depuis toujours intéressés en l'aptitude d'une population à répondre à la sélection naturelle. Cette réponse dépend de la quantité de variabilité génétique présente dans cette population. Plus particulièrement, les théoriciens se sont penchés sur la question du maintient de la variabilité génétique au sein d'environnements hétérogènes. Ils ont alors démontré que, sous certaines conditions, la diversité génétique peut se maintenir de manière stable et permanente dans des environnements variant au niveau spatial et temporel. De plus, ces environments variables ont été démontrés comme responsable de divergence de traits d'histoire de vie au sein des différentes niches constituant l'environnement. Cependant, malgré ce nombre important d'études théoriques portant sur la sélection et l'évolution des traits d'histoire de vie en environnement hétérogène, les études empiriques sont plus rares. Le but de cette thèse était donc d'étudier les conséquences évolutives d'un environnement hétérogène chez un esgarcot d'eau douce Galba truncatula. En effet, G. truncatula est trouvé dans deux types d'habitats qui diffèrent par leur niveau d'eau. Le premier, l'habitat temporaire, est constitué de flaques d'eau qui peuvent s'assécher pendant l'été et geler pendant l'hiver. Le second, l'habitat permanent, correspond à des marres ou à des ruisseaux qui ont un niveau d'eau constant durant toute l'année. Utilisant une approche expérimentale de type "jardin commun", nous avons démontré l'adaptation locale des individus à leur type d'habitat, permanent ou temporaire. Nous avons utilisé l'approche Fsr/QsT qui compare la différentiation génétique moléculaire avec la différentiation génétique quantitative entre les 2 habitats. Le phénomène d'adapation locale démontré par QsT > FsT, a été testé experimentalement en mesurant la résistance à la dessiccation d'individus d'habitat temporaire et permanent. Cette étude confirma que la résistance à la sécheresse a été sélectionné entre habitats et que les traits responsables de cette resistance sont différents entre habitats. Cependant si la sélection agit sur la valeur moyenne des traits entre habitats, la dérive génétique semble être le responsable majeur de la différence de variances-covariances entre populations. Pour finir, une variation de traits d'histoire de vie a été trouvée au sein d'un environnement hétérogène constitué de populations variants au niveau de leur taux de parasitisme. Pour conclure, cette thèse a donc démontré l'importance d'un environnement hétérogène sur l'adaptation locale et l'évolution des traits d'histoire de vie et suggère que plus d'études empiriques sur le sujet sont nécessaires.