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Watonwan County: Overview of Nitrate Levels in Private Wells (2019)
Watonwan County: Overview of Nitrate Levels in Private Wells (2019)
Yes, Summary, Riverdale Township was selected by the MDA for testing based on its vulnerable geology and row crop agriculture. The initial sampling in Watonwan County started in 2019 and follow-up sampling is scheduled for 2020., Full text
Watonwan River Watershed Hydrology, Connectivity, and Geomorphology Assessment Report
Watonwan River Watershed Hydrology, Connectivity, and Geomorphology Assessment Report
The Watonwan River watershed is an eight-digit Hydrologic Unit Code (HUC) watershed draining approximately 878 mi2 of predominantly agricultural land in south-central Minnesota. The following report analyzes the hydrology, connectivity, and geomorphology components of the Watonwan River watershed. Historical gage data on the Watonwan River, stream crossing data, and applied fluvial geomorphology assessments were analyzed to characterize conditions of the watershed and find relationships to help understand water quality and biological impairments throughout the watershed. Discharge and precipitation data collected from the Watonwan River indicate the amount and timing of water delivered per inch of precipitation has increased over time. This increased volume and rate of water delivery can further destabilize the river system, and is a contributing factor to the geomorphic response within the watershed. Investigation of the longitudinal connectivity of the Watonwan watershed indicated a bridge density of 0.20/mi2, and a culvert density of 0.17/mi2. Furthermore, 11 dams are located in the Watonwan watershed; 2 of the dams are potential barriers to fish passage at most water levels. Fluvial geomorphology survey results indicated 7 of 11 survey reaches have lateral floodplain connectivity. Evidence of past channelization at or near geomorphology field sites was apparent at 10 of 11 reaches surveyed. According to the Minnesota Pollution Control Agency (MPCA), 70% of the Watonwan watershed has altered watercourses (e.g., channelized or impounded). Channelized systems have limited floodplain connectivity and are often incorrectly sized (e.g., cross sectional area to drainage area, width/depth ratios), not allowing the channel to effectively transport the sediments of its watershed. Rivers and streams in the Watonwan watershed that are maintaining deep-rooted perennial vegetated riparian corridors, and those able to access their floodplains to dissipate energy during high flows, are showing greater sign of stream stability. Overall, the objective is to improve the health of the watershed, to enhance agricultural sustainability, groundwater conservation, fish and wildlife habitat, biodiversity, recreation, and water quality throughout the watershed. As important as the restoration of disturbed areas is, focus must also be set to protect undisturbed areas generating multiple ecosystem services that appear to be near reference condition. Instability was documented at several of the survey sites"
Well Owner’s Handbook A Consumer’s Guide to Water Wells in Minnesota
Well Owner’s Handbook A Consumer’s Guide to Water Wells in Minnesota
Summary, Minnesota’s drinking water comes either from surface water (lakes, streams, or rivers) or from groundwater. Surface water is more vulnerable to contamination and requires extensive testing and treatment to assure that it is safe to drink. Groundwater obtained from a well is usually safe to drink without treatment, if the well has been properly constructed and maintained. Seventy percent of the people in Minnesota obtain their drinking water from groundwater, either from private or public wells. Groundwater and surface water are both part of the “hydrologic cycle,” which is illustrated in Figure 1. Water rises from the earth’s surface as evaporation and falls to the earth as precipitation, in the form of snow or rain. Water that falls on the ground either moves over the ground as runoff or down through the soil to the saturated zone through infiltration — and then through an aquifer to an area of discharge, such as a river, lake, or pumping well. As the name implies, groundwater is found beneath the land surface — in cracks and crevices in bedrock, or in pore spaces, which are the small spaces between soil or rock particles in sand and gravel deposits. Surface water becomes groundwater when it seeps downward to the saturated zone. The saturated zone begins at the point where the pore spaces and cracks in the soil, sediment, or rock become completely filled with water. The top of this zone is called the water table. An aquifer is a layer of sediment, such as sand or gravel, or a layer of rock, such as sandstone, that stores and transmits water to a well. A confining layer is a layer of sediment or rock that slows or prevents the downward movement of water — a thick layer of clay is an example of a confining layer. Geologic conditions vary greatly in different parts of Minnesota. As a result, well depth, well construction, and natural water quality also vary. Most wells in Minnesota draw water from sand and gravel layers that were deposited by the melting of glaciers during past ice ages. Glacial deposits range in thickness from very thin or absent in the eastern part of the state to over 1,000 feet in the west. Wells in southeastern and east central Minnesota, including the Twin Cities metropolitan area, often draw water from sandstone and limestone rock formations which underlie the glacial deposits. In northeastern Minnesota, the St. Cloud area, and the Minnesota River Valley, wells often draw water from fractured rocks such as granite. Information concerning the geology and groundwater resources in your area may be obtained from a licensed well contractor, the Minnesota Department of Health offices listed on page 35, delegated well programs listed on page 36, or the Minnesota Geological Survey at 612-627-4784. The quality of groundwater depends on the type of soil, sediment, or rock through which the water is moving, the length of time water is in contact with geologic materials, and whether any contaminants are present. Gases, minerals, and other chemicals may dissolve into water as it moves underground. The quality of Minnesota groundwater as it relates to human health is generally very good. Bacteria, viruses, and many chemical contaminants are removed or filtered from the water as it moves downward through silt, sand, and gravel deposits. Observing minimum isolation distances (also known as setback or separation distances) from contamination sources (Figure 2) — and well construction standards required under Minnesota Rules, Chapter 4725 (the “Well Code”) — will help assure that the quality of the well water remains high., Full text
Well characteristics influencing arsenic concentrations
in ground water
Well characteristics influencing arsenic concentrations in ground water
Naturally occurring arsenic contamination is common in ground water in the upper Midwest. Arsenic is most likely to be present in glacial drift and shallow bedrock wells that lie within the footprint of northwest provenance Late Wisconsinan glacial drift. Elevated arsenic is more common in domestic wells and in monitoring wells than it is in public water system wells. Arsenic contamination is also more prevalent in domestic wells with short screens set in proximity to an upper confining unit, such as glacial till. Public water system wells have distinctly different well-construction practices and well characteristics when compared to domestic and monitoring wells. Construction practices such as exploiting a thick, coarse aquifer and installing a long well screen yield good water quantity for public water system wells. Coincidentally, these construction practices also often yield low arsenic water. Coarse aquifer materials have less surface area for adsorbing arsenic, and thus less arsenic available for potential mobilization. Wells with long screens set at a distance from an upper confining unit are at lower risk of exposure to geochemical conditions conducive to arsenic mobilization via reductive mechanisms such as reductive dissolution of metal hydroxides and reductive desorption of arsenic.
Wet Atmospheric Deposition of Pesticides in Minnesota, 1989-94
Wet Atmospheric Deposition of Pesticides in Minnesota, 1989-94
Abstract, All of the rain samples during the growing season had detectable quantities of at least one pesticide, but most of the pesticides were only infrequently observed. The most frequently detected compounds were the herbicides alachlor, atrazine, cyanazine, and metolachlor, and in 1994, its first year of registration, acetochlor. Peak concentrations of most herbicides in rainfall occurred shortly after their application periods in the spring. Peak concentrations of most of the insecticides occurred later in the summer. The majority of the wet depositional flux of pesticides occurred between early May and October. The annual wet depositional flux of pesticides is 5 orders of magnitude less than is the "annual flux" normally applied on an agricultural field, although some of the pesticides in rain are deposited in areas far removed from agricultural fields. The annual variability in pesticide deposition can be explained by year-to-year differences in climate and pesticide use patterns. The one sampling site (Lamberton) that was in an area dominated by row crop agriculture showed a significantly greater annual flux than the other four sampling sites that were in areas of either urbanization or less intensive agricultural. Regional deposition, away from a local source, can be inferred from these four sites because they have annual pesticide fluxes that are very similar for any given year. The observation of agricultural pesticides (not registered for home and garden use) in rain and storm runoff in the urban area indicates their transport from areas of agricultural use. Urban areas may be the best locations for assessing changes in regional use and deposition of agricultural pesticides. The pesticide fluxes in the streams out of the small three watersheds was compared to the pesticide flux into the watersheds in rain. The data indicate that flux into the watersheds from the rain is generally much greater than the flux from the watersheds in the streams. Therefore, a large fraction of the pesticides deposited in rain is retained within the watersheds. For the urban area, this is on the order of 98 percent for the four most commonly observed herbicides in rain and runoff., Full text
Wet Meadow Revegetation Following Invasive Plant Control
Wet Meadow Revegetation Following Invasive Plant Control
Yes, Abstract, Phalaris arundinacea invades sedge meadow restorations, forming persistent monotypes that prevent community establishment. Eradicating Phalaris, however, leaves restored ecosystems prone to reinvasion. In order to restore desired plant communities, methods to control Phalaris are needed. To determine if reducing light by sowing cover crops and reducing nitrogen by incorporating soil-sawdust amendments would prevent Phalaris invasions, a study was conducted under conditions similar to a restored wetland in two experimental basins with controlled hydrology. Seeds of a 10-species target community and Phalaris were sown in plots with high diversity, low diversity, or no cover crops in soils with or without sawdust amendments. Nitrogen, light, tissue C:N ratios, firstyear seedling emergence, establishment, and growth, and second-year above ground biomass were measured. Only high diversity cover crops reduced light and sawdust reduced nitrogen for about 9 weeks. Similar trends in firstyear seedling data and second-year biomass data suggested Phalaris control efforts should focus on establishing perennial communities rather than implementing separate resource-limiting strategies. Sowing high diversity cover crops resulted in Phalaris-dominated communities, making cover crops an ineffective Phalaris control strategy. Using sawdust amendments did not reduce Phalaris invasion much beyond what the target community did but resulted in a community similar to those of natural sedge meadows by increasing the abundance of seeded species from the Cyperaceae family and colonization of non-seeded wetland species. The target community apparently reduced Phalaris invasion by reducing both light and nitrogen. Regardless, no treatment fully prevented invasion, making follow-up Phalaris control necessary to ensure community recovery., Full text
Wet Weather Flow Assessment Protocols
Wet Weather Flow Assessment Protocols
This final report presents methods for characterizing nonpoint and point sources of wet weather flows (WWFs), assessing effects of WWF-induced pollution on receiving water systems, and evaluating WWF control practices and treatment technologies. This work was based on the fact that many water quality and ecosystem problems are best solved at the watershed level than at the individual waterbody or discharger level, and ideally a framework investigation should be completed for the entire watershed before details of individual pollution sources or waterbodies are addressed. Published by WERF. 122 pages. Soft cover.
Wetland Controlled Grazing Study
Wetland Controlled Grazing Study
Yes, Summary, The effects of grazing in wetlands is being studied as a management strategy for controlling non-native cool season grasses. Non-native grasses including reed canary grass, Kentucky bluegrass and smooth brome grass are common invaders of restored wetlands and upland buffers. Controlled grazing can be used to set back these grasses if focused during times of the year when they are active., Full text

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