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joseph eilers

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I am focused on providing on providing high quality data for resource management decisions. particularly related to limnology and aquatic ecology. I have professional registrations in hydrology (water quality), fisheries and lake management. The types of data acquisition I deal with include lake and riverine assessment using paleolimnology, targeted monitoring, hydroacoustics, analysis of hydroelectric projects and numerical modeling of water quality. Geographic range of most studies range from Mexico to Alaska, with emphasis on the Pacific Northwest.
Address: Bend, Oregon, United States

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Mechanical Removal of Minnows (Gila bicolor) to Improve Water Quality in a Hydropower Impoundment, Lemolo Lake, Oregon, USA

Hydrobiology

A project to mechanically remove an over-abundant population of cyprinids (Gila bicolor) was test... more A project to mechanically remove an over-abundant population of cyprinids (Gila bicolor) was tested in a hydropower impoundment, Lemolo Lake (USA). The netting program removed 29.7 tons of fish (163 kg/ha) over a seven-year period that resulted in a reduction in the intensity and duration of cyanobacteria blooms. However, the suppression of the tui chub population apparently allowed for a residual population of kokanee (Oncorhynchus nerka) to proliferate. The resurgence of the kokanee, combined with the initiation of a rainbow trout stocking program, offset some of the gains in water quality achieved with the reduction of tui chub biomass. The dominant cyanobacterium present in Lemolo Lake transitioned to Gloeotrichia echinulata in 2013, but the majority of these colonies were apparently derived from an upstream lake. The changes in water quality from 2005–2013 were simulated for Lemolo Lake using the two-dimensional, hydrodynamic model, CE-QUAL-W2. The model reproduced many aspects...

Harmful Cyanobacteria in Three Oregon Lakes: Comments on Hall et al. Beyond Water Quality Advisories and Total Maximum Daily Loads (TMDLs). Water 2019, 11, 1125

Water, Nov 25, 2019

The article "An Ecological Function Approach to Managing Harmful Cyanobacteria in Three Oregon La... more The article "An Ecological Function Approach to Managing Harmful Cyanobacteria in Three Oregon Lakes: Beyond Water Quality Advisories and Total Maximum Daily Loads (TMDLs), Water 11:1125" by Hall et al. critiques the current approach used by the state of Oregon with regard to managing cyanobacterial blooms and offers the proper functioning condition (PVC) as a superior method of managing cyanobacterial blooms in lakes derived from nonpoint sources of pollution. They evaluated three lakes in Oregon as examples of how this approach could be applied to support water quality improvement. Two of the three lakes, Lemolo and Diamond, experienced cyanobacterial blooms, not as a function of nonpoint source loadings from the watershed, but rather because of internal nutrient cycling associated with high fish biomass. The third lake, Tenmile Lakes, in additional to having a greatly altered fish community, also experiences cyanobacterial blooms (CyanoHABs) issues because of timber harvest on steep slopes, loss of wetlands, altered watershed hydrology and nutrient input from septic systems. The authors' attempts to use satellite images and PVC methodology on the stream networks is incomplete with respect to Tenmile Lakes and is totally misdirected regarding Lemolo and Diamond Lakes. Although I don't support the current system employed by the state of Oregon to manage lakes experiencing CyanoHABs issues, the proposed approach offered by staff with the U.S. Environmental Protection Agency will yield little water quality benefit for the lakes in question.

Eradication of an invasive cyprinid (Gila bicolor) to achieve water quality goals in Diamond Lake, Oregon (USA)

Lake and Reservoir Management, 2011

Eilers JM, Truemper HA, Jackson LS, Eilers BJ, Loomis DW. 2011. Eradication of an invasive cyprin... more Eilers JM, Truemper HA, Jackson LS, Eilers BJ, Loomis DW. 2011. Eradication of an invasive cyprinid (Gila bicolor) to achieve water quality goals in Diamond Lake, Oregon (USA). Lake Reserv Manage. 27:194-204. We used a case study of whole-lake fish removal to demonstrate the importance of the fish community to nutrient cycling in Diamond Lake, Oregon, USA, to meet regulated water quality standards for pH, dissolved oxygen and nuisance algae. The cyprinid tui chub (Gila bicolor) was removed through a process beginning with netting and ending with a whole-lake and tributary rotenone treatment in September 2006. The lake was stocked with rainbow trout in spring 2007. Between 2007 and 2009, lake transparency increased 250%, accompanied by decreases in epilimnetic pH, total nitrogen, and total organic carbon. Mean concentrations of total phosphorus and ortho-phosphorus remained unchanged in epilimnetic waters. Chlorophyll a, phytoplankton biovolume, Anabaena biovolume, and Anabaena cell density declined. Daphnia pulicaria, a large herbivorous cladoceran virtually absent for 10 years, returned in abundance, and benthic biomass increased more than 12-fold. The project successfully demonstrated that water quality and fishery goals can be met through eradication of the invasive cyprinid. Fish populations need to be considered in some lakes to achieve water quality standards.

Paleolimnological evidence of change in a shallow, hypereutrophic lake: Upper Klamath Lake, Oregon, USA

Hydrobiologia, 2004

Sediment cores were collected from Upper Klamath Lake in October, 1998 and analyzed for 210 Pb, 1... more Sediment cores were collected from Upper Klamath Lake in October, 1998 and analyzed for 210 Pb, 14 C, 15 N, N, P, C, Ti, Al, diatoms, Pediastrum, and cyanobacterial akinetes. These results were used to reconstruct changes in water quality in Upper Klamath Lake over the last 150 years. The results showed that there was substantial mixing of the upper 10 cm of sediment, representing the previous 20 to 30 years. However, below that, 210 Pb activity declined monotonically, allowing reasonable dating for the period from about 1850 to 1970. The sediment accumulation rates (SAR) showed a substantial increase in the 20th century. The increase in SAR corresponded with increases in erosional input from the watershed as represented by the increases in sediment concentrations of Ti and Al. The upper 20 cm of sediment, representing the last 150 years, also showed increases in C, N, P, and 15 N. The increases in nutrient concentrations may be affected to various degrees by diagenetic reactions within the sediments, although the changes in concentrations also were marked by changes in the N:P ratio and in a qualitative change in the source of N as reflected in increasing δ 15 N. The diatoms showed modest changes in the 20th century, with increases in Asterionella formosa, Stephanodiscus hantzschii, and S. parvus. Pediastrum, a green alga, was well-preserved in the sediments and exhibited a sharp decline in relative abundance in the upper sediments. Total cyanobacteria, as represented by preserved akinetes, exhibited only minor changes in the last 1000 years. However, Aphanizomenon flos-aquae, a taxon which was formerly not present in the lake 150 years ago, but that now dominates the summer phytoplankton, has shown major increases over the past 100 years. The changes in sediment composition are consistent with activities including timber harvest, drainage of wetlands, and agricultural activities associated with livestock grazing, irrigated cropland, and hydrologic modifications.

Assessing the Chemical and Biological Resilience of Lakes in the Cascade Range to Acidic Deposition

Water, Air, & Soil Pollution, 2016

Regional chemical characteristics of lakes in North America: Part Ieastern Canada

Water, Air, & Soil …, 1986

... DL Wales Fisheries Research Branch Ontario Ministry of Natural Resources Queen&amp;#x27;s... more

Recent Desiccation-Related Ecosystem Changes at Lake Abert, Oregon: A Terminal Alkaline Salt Lake

Western North American Naturalist

Major Ion Chemistry of Lakes on the Kenai Peninsula, Alaska

by M. S. Jesse Ford and joseph eilers

Canadian Journal of Fisheries and Aquatic Sciences, 1993

We characterized the major ion chemistry of over 800 lakes on the Kenai Peninsula, Alaska, from a... more We characterized the major ion chemistry of over 800 lakes on the Kenai Peninsula, Alaska, from a probability sample of 59 lakes (August 1988). There were two groups: alkalinity 700 μeq/L. Low-alkalinity lakes had significantly lower concentrations of base cations and silica and significantly higher average concentrations of dissolved organic carbon (DOC) than high-alkalinity lakes. Despite widespread acidic soils and bog vegetation, and resulting high DOC concentrations, none of the lakes sampled was acidic. Sulfate concentrations (~3 μeq/L) were similar in the two groups, as were Cl− concentrations, which decreased with distance from the coast. High-alkalinity lakes were similar chemically to rivers and shallow aquifers in the region, suggesting that the high alkalinity is a product of the major weathering reactions in this terrain; the substantially different ratios of base cations in the two groups also indicate quantitative and qualitative weathering differences. Low-alkalinit...

The inapplicability of the Gibbs model of world water chemistry for dilute lakes

by Arne Henriksen and joseph eilers

Limnology and Oceanography, 1992

Guidelines for evaluating air pollution impacts on class I wilderness areas in California

Geographic Overview of the Regional Case Study Areas

Acidic Deposition and Aquatic Ecosystems, 1991

ABSTRACT

Changes in Conductivity, Alkalinity, Calcium, and pH During a 50-Year Period in Selected Northern Wisconsin Lakes

Can J Fisheries Aquat Sci, 1989

Between 1925 and 1941 extensive water quality measurements were made on over 600 northern Wiscons... more Between 1925 and 1941 extensive water quality measurements were made on over 600 northern Wisconsin lakes, providing a benchmark against which comparisons can be made if the modern equivalent measurements can be determined. Of these 149 lakes were sampled from 1979 to 1983. Data on conductivity, alkalinity, calcium, and hydrogen ion (pH) are available for these lakes from 1925 to

Modification of Early-Postmortem Muscle pH and Use of Postmortem Aging to Improve Beef Tenderness 1,2

beef tenderness Modification of early-postmortem muscle pH and use of postmortem aging to improve... more

Major ion chemistry of lakes on the Kenai Peninsula, Alaska

Can J Fisheries Aquat Sci, 1993

and ). Ford. 1993. Major ion chemistry sf lakes on the Kenai Peninsula, Alaska. Caw. 1. Fish. Aqu... more

Recent wetlands trends (1981/82�1994) in the Willamette Valley, Oregon, USA

Wetlands, Sep 1, 1999

A two-stage, stratified, systematic sample design was implemented in the Willamette Valley,

Organic acid modeling and model validation: Workshop summary. Final report

A workshop was held in Corvallis, Oregon on April 9--10, 1992 at the offices of E S Environmental... more A workshop was held in Corvallis, Oregon on April 9--10, 1992 at the offices of E S Environmental Chemistry, Inc. The purpose of this workshop was to initiate research efforts on the entitled Incorporation of an organic acid representation into MAGIC (Model of Acidification of Groundwater in Catchments) and testing of the revised model using Independent data sources.&#x27;&#x27; The workshop was attended by a team of internationally-recognized experts in the fields of surface water acid-bass chemistry, organic acids, and watershed modeling. The rationale for the proposed research is based on the recent comparison between MAGIC model hindcasts and paleolimnological inferences of historical acidification for a set of 33 statistically-selected Adirondack lakes. Agreement between diatom-inferred and MAGIC-hindcast lakewater chemistry in the earlier research had been less than satisfactory. Based on preliminary analyses, it was concluded that incorporation of a reasonable organic acid representation into the version of MAGIC used for hindcasting was the logical next step toward improving model agreement.

Evaluation of the role of sea salt inputs in the long-term acidification of coastal New England lakes

Environmental Science and Technology, Feb 1, 1988

Process for reducing Ramsbottom Carbon Test of short residues

ABSTRACT

Characteristics of lakes in mountainous areas of the western United States (journal version)

The U.S. Environmental Protection Agency (EPA) initiated the National Lake Survey to quantify the... more The U.S. Environmental Protection Agency (EPA) initiated the National Lake Survey to quantify the number, location, and characteristics of lakes in the United States with little or no acid neutralizing capacity (ANC). Presumably, the lakes with low ANC are at greatest risk to acidification from atmospheric deposition. In autumn 1984, EPA sampled 1792 lakes in the eastern United States; those results are reported in Linthurst et al. (1986). The companion project of the Eastern Lake Survey is the Western Lake Survey, conducted in autumn of 1985. The purpose of the paper is to present results of the Western Lake Survey and to illustrate the characteristics of these lakes in the context of acidic-deposition impacts.

Water Quality Modeling of Alternative Agricultural Scenarios in the U.S. Corn Belt

Journal of the American Water Resources Association, 2002

Simulated water quality resulting from three alternative future land-use scenarios for two agricu... more Simulated water quality resulting from three alternative future land-use scenarios for two agricultural watersheds in central Iowa was compared to water quality under current and historic land use/land cover to explore both the potential water quality impact of perpetuating current trends and potential benefits of major changes in agricultural practices in the U.S. Corn Belt. The Soil Water Assessment Tool (SWAT) was applied to evaluate the effect of management practices on surface water discharge and annual loads of sediment and nitrate in these watersheds. The agricultural practices comprising Scenario 1, which assumes perpetuation of current trends (conversion to conservation tillage, increase in farm size and land in production, use of currently-employed Best Management Practices (BMPs)) result in simulated increased export of nitrate and decreased export of sediment relative to the present. However, simulations indicate that the substantial changes in agricultural practices envisioned in Scenarios 2 and 3 (conversion to conservation tillage, strip intercropping, rotational grazing, conservation set-asides and greatly extended use of best management practices (BMPs) such as riparian buffers, engineered wetlands, grassed waterways, filter strips and field borders) could potentially reduce current loadings of sediment by 37 to 67 percent and nutrients by 54 to 75 percent. Results from the study indicate that major improvements in water quality in these agricultural watersheds could be achieved if such environmentally-targeted agricultural practices were employed. Traditional approaches to water quality improvement through application of traditional BMPs will result in little or no change in nutrient export and minor decreases in sediment export from Corn Belt watersheds. (KEY TERMS: watershed management; future scenarios; agricultural watersheds; modeling; water quality; SWAT.) 1 Paper No.

Mechanical Removal of Minnows (Gila bicolor) to Improve Water Quality in a Hydropower Impoundment, Lemolo Lake, Oregon, USA

Hydrobiology

A project to mechanically remove an over-abundant population of cyprinids (Gila bicolor) was test... more A project to mechanically remove an over-abundant population of cyprinids (Gila bicolor) was tested in a hydropower impoundment, Lemolo Lake (USA). The netting program removed 29.7 tons of fish (163 kg/ha) over a seven-year period that resulted in a reduction in the intensity and duration of cyanobacteria blooms. However, the suppression of the tui chub population apparently allowed for a residual population of kokanee (Oncorhynchus nerka) to proliferate. The resurgence of the kokanee, combined with the initiation of a rainbow trout stocking program, offset some of the gains in water quality achieved with the reduction of tui chub biomass. The dominant cyanobacterium present in Lemolo Lake transitioned to Gloeotrichia echinulata in 2013, but the majority of these colonies were apparently derived from an upstream lake. The changes in water quality from 2005–2013 were simulated for Lemolo Lake using the two-dimensional, hydrodynamic model, CE-QUAL-W2. The model reproduced many aspects...

Harmful Cyanobacteria in Three Oregon Lakes: Comments on Hall et al. Beyond Water Quality Advisories and Total Maximum Daily Loads (TMDLs). Water 2019, 11, 1125

Water, Nov 25, 2019

The article "An Ecological Function Approach to Managing Harmful Cyanobacteria in Three Oregon La... more The article "An Ecological Function Approach to Managing Harmful Cyanobacteria in Three Oregon Lakes: Beyond Water Quality Advisories and Total Maximum Daily Loads (TMDLs), Water 11:1125" by Hall et al. critiques the current approach used by the state of Oregon with regard to managing cyanobacterial blooms and offers the proper functioning condition (PVC) as a superior method of managing cyanobacterial blooms in lakes derived from nonpoint sources of pollution. They evaluated three lakes in Oregon as examples of how this approach could be applied to support water quality improvement. Two of the three lakes, Lemolo and Diamond, experienced cyanobacterial blooms, not as a function of nonpoint source loadings from the watershed, but rather because of internal nutrient cycling associated with high fish biomass. The third lake, Tenmile Lakes, in additional to having a greatly altered fish community, also experiences cyanobacterial blooms (CyanoHABs) issues because of timber harvest on steep slopes, loss of wetlands, altered watershed hydrology and nutrient input from septic systems. The authors' attempts to use satellite images and PVC methodology on the stream networks is incomplete with respect to Tenmile Lakes and is totally misdirected regarding Lemolo and Diamond Lakes. Although I don't support the current system employed by the state of Oregon to manage lakes experiencing CyanoHABs issues, the proposed approach offered by staff with the U.S. Environmental Protection Agency will yield little water quality benefit for the lakes in question.

Eradication of an invasive cyprinid (Gila bicolor) to achieve water quality goals in Diamond Lake, Oregon (USA)

Lake and Reservoir Management, 2011

Eilers JM, Truemper HA, Jackson LS, Eilers BJ, Loomis DW. 2011. Eradication of an invasive cyprin... more Eilers JM, Truemper HA, Jackson LS, Eilers BJ, Loomis DW. 2011. Eradication of an invasive cyprinid (Gila bicolor) to achieve water quality goals in Diamond Lake, Oregon (USA). Lake Reserv Manage. 27:194-204. We used a case study of whole-lake fish removal to demonstrate the importance of the fish community to nutrient cycling in Diamond Lake, Oregon, USA, to meet regulated water quality standards for pH, dissolved oxygen and nuisance algae. The cyprinid tui chub (Gila bicolor) was removed through a process beginning with netting and ending with a whole-lake and tributary rotenone treatment in September 2006. The lake was stocked with rainbow trout in spring 2007. Between 2007 and 2009, lake transparency increased 250%, accompanied by decreases in epilimnetic pH, total nitrogen, and total organic carbon. Mean concentrations of total phosphorus and ortho-phosphorus remained unchanged in epilimnetic waters. Chlorophyll a, phytoplankton biovolume, Anabaena biovolume, and Anabaena cell density declined. Daphnia pulicaria, a large herbivorous cladoceran virtually absent for 10 years, returned in abundance, and benthic biomass increased more than 12-fold. The project successfully demonstrated that water quality and fishery goals can be met through eradication of the invasive cyprinid. Fish populations need to be considered in some lakes to achieve water quality standards.

Paleolimnological evidence of change in a shallow, hypereutrophic lake: Upper Klamath Lake, Oregon, USA

Hydrobiologia, 2004

Sediment cores were collected from Upper Klamath Lake in October, 1998 and analyzed for 210 Pb, 1... more Sediment cores were collected from Upper Klamath Lake in October, 1998 and analyzed for 210 Pb, 14 C, 15 N, N, P, C, Ti, Al, diatoms, Pediastrum, and cyanobacterial akinetes. These results were used to reconstruct changes in water quality in Upper Klamath Lake over the last 150 years. The results showed that there was substantial mixing of the upper 10 cm of sediment, representing the previous 20 to 30 years. However, below that, 210 Pb activity declined monotonically, allowing reasonable dating for the period from about 1850 to 1970. The sediment accumulation rates (SAR) showed a substantial increase in the 20th century. The increase in SAR corresponded with increases in erosional input from the watershed as represented by the increases in sediment concentrations of Ti and Al. The upper 20 cm of sediment, representing the last 150 years, also showed increases in C, N, P, and 15 N. The increases in nutrient concentrations may be affected to various degrees by diagenetic reactions within the sediments, although the changes in concentrations also were marked by changes in the N:P ratio and in a qualitative change in the source of N as reflected in increasing δ 15 N. The diatoms showed modest changes in the 20th century, with increases in Asterionella formosa, Stephanodiscus hantzschii, and S. parvus. Pediastrum, a green alga, was well-preserved in the sediments and exhibited a sharp decline in relative abundance in the upper sediments. Total cyanobacteria, as represented by preserved akinetes, exhibited only minor changes in the last 1000 years. However, Aphanizomenon flos-aquae, a taxon which was formerly not present in the lake 150 years ago, but that now dominates the summer phytoplankton, has shown major increases over the past 100 years. The changes in sediment composition are consistent with activities including timber harvest, drainage of wetlands, and agricultural activities associated with livestock grazing, irrigated cropland, and hydrologic modifications.

Assessing the Chemical and Biological Resilience of Lakes in the Cascade Range to Acidic Deposition

Water, Air, & Soil Pollution, 2016

Regional chemical characteristics of lakes in North America: Part Ieastern Canada

Water, Air, & Soil …, 1986

... DL Wales Fisheries Research Branch Ontario Ministry of Natural Resources Queen&amp;#x27;s... more

Recent Desiccation-Related Ecosystem Changes at Lake Abert, Oregon: A Terminal Alkaline Salt Lake

Western North American Naturalist

Major Ion Chemistry of Lakes on the Kenai Peninsula, Alaska

by M. S. Jesse Ford and joseph eilers

Canadian Journal of Fisheries and Aquatic Sciences, 1993

We characterized the major ion chemistry of over 800 lakes on the Kenai Peninsula, Alaska, from a... more We characterized the major ion chemistry of over 800 lakes on the Kenai Peninsula, Alaska, from a probability sample of 59 lakes (August 1988). There were two groups: alkalinity 700 μeq/L. Low-alkalinity lakes had significantly lower concentrations of base cations and silica and significantly higher average concentrations of dissolved organic carbon (DOC) than high-alkalinity lakes. Despite widespread acidic soils and bog vegetation, and resulting high DOC concentrations, none of the lakes sampled was acidic. Sulfate concentrations (~3 μeq/L) were similar in the two groups, as were Cl− concentrations, which decreased with distance from the coast. High-alkalinity lakes were similar chemically to rivers and shallow aquifers in the region, suggesting that the high alkalinity is a product of the major weathering reactions in this terrain; the substantially different ratios of base cations in the two groups also indicate quantitative and qualitative weathering differences. Low-alkalinit...

The inapplicability of the Gibbs model of world water chemistry for dilute lakes

by Arne Henriksen and joseph eilers

Limnology and Oceanography, 1992

Guidelines for evaluating air pollution impacts on class I wilderness areas in California

Geographic Overview of the Regional Case Study Areas

Acidic Deposition and Aquatic Ecosystems, 1991

ABSTRACT

Changes in Conductivity, Alkalinity, Calcium, and pH During a 50-Year Period in Selected Northern Wisconsin Lakes

Can J Fisheries Aquat Sci, 1989

Between 1925 and 1941 extensive water quality measurements were made on over 600 northern Wiscons... more Between 1925 and 1941 extensive water quality measurements were made on over 600 northern Wisconsin lakes, providing a benchmark against which comparisons can be made if the modern equivalent measurements can be determined. Of these 149 lakes were sampled from 1979 to 1983. Data on conductivity, alkalinity, calcium, and hydrogen ion (pH) are available for these lakes from 1925 to

Modification of Early-Postmortem Muscle pH and Use of Postmortem Aging to Improve Beef Tenderness 1,2

beef tenderness Modification of early-postmortem muscle pH and use of postmortem aging to improve... more

Major ion chemistry of lakes on the Kenai Peninsula, Alaska

Can J Fisheries Aquat Sci, 1993

and ). Ford. 1993. Major ion chemistry sf lakes on the Kenai Peninsula, Alaska. Caw. 1. Fish. Aqu... more

Recent wetlands trends (1981/82�1994) in the Willamette Valley, Oregon, USA

Wetlands, Sep 1, 1999

A two-stage, stratified, systematic sample design was implemented in the Willamette Valley,

Organic acid modeling and model validation: Workshop summary. Final report

A workshop was held in Corvallis, Oregon on April 9--10, 1992 at the offices of E S Environmental... more A workshop was held in Corvallis, Oregon on April 9--10, 1992 at the offices of E S Environmental Chemistry, Inc. The purpose of this workshop was to initiate research efforts on the entitled Incorporation of an organic acid representation into MAGIC (Model of Acidification of Groundwater in Catchments) and testing of the revised model using Independent data sources.&#x27;&#x27; The workshop was attended by a team of internationally-recognized experts in the fields of surface water acid-bass chemistry, organic acids, and watershed modeling. The rationale for the proposed research is based on the recent comparison between MAGIC model hindcasts and paleolimnological inferences of historical acidification for a set of 33 statistically-selected Adirondack lakes. Agreement between diatom-inferred and MAGIC-hindcast lakewater chemistry in the earlier research had been less than satisfactory. Based on preliminary analyses, it was concluded that incorporation of a reasonable organic acid representation into the version of MAGIC used for hindcasting was the logical next step toward improving model agreement.

Evaluation of the role of sea salt inputs in the long-term acidification of coastal New England lakes

Environmental Science and Technology, Feb 1, 1988

Process for reducing Ramsbottom Carbon Test of short residues

ABSTRACT

Characteristics of lakes in mountainous areas of the western United States (journal version)

The U.S. Environmental Protection Agency (EPA) initiated the National Lake Survey to quantify the... more The U.S. Environmental Protection Agency (EPA) initiated the National Lake Survey to quantify the number, location, and characteristics of lakes in the United States with little or no acid neutralizing capacity (ANC). Presumably, the lakes with low ANC are at greatest risk to acidification from atmospheric deposition. In autumn 1984, EPA sampled 1792 lakes in the eastern United States; those results are reported in Linthurst et al. (1986). The companion project of the Eastern Lake Survey is the Western Lake Survey, conducted in autumn of 1985. The purpose of the paper is to present results of the Western Lake Survey and to illustrate the characteristics of these lakes in the context of acidic-deposition impacts.

Water Quality Modeling of Alternative Agricultural Scenarios in the U.S. Corn Belt

Journal of the American Water Resources Association, 2002

Simulated water quality resulting from three alternative future land-use scenarios for two agricu... more Simulated water quality resulting from three alternative future land-use scenarios for two agricultural watersheds in central Iowa was compared to water quality under current and historic land use/land cover to explore both the potential water quality impact of perpetuating current trends and potential benefits of major changes in agricultural practices in the U.S. Corn Belt. The Soil Water Assessment Tool (SWAT) was applied to evaluate the effect of management practices on surface water discharge and annual loads of sediment and nitrate in these watersheds. The agricultural practices comprising Scenario 1, which assumes perpetuation of current trends (conversion to conservation tillage, increase in farm size and land in production, use of currently-employed Best Management Practices (BMPs)) result in simulated increased export of nitrate and decreased export of sediment relative to the present. However, simulations indicate that the substantial changes in agricultural practices envisioned in Scenarios 2 and 3 (conversion to conservation tillage, strip intercropping, rotational grazing, conservation set-asides and greatly extended use of best management practices (BMPs) such as riparian buffers, engineered wetlands, grassed waterways, filter strips and field borders) could potentially reduce current loadings of sediment by 37 to 67 percent and nutrients by 54 to 75 percent. Results from the study indicate that major improvements in water quality in these agricultural watersheds could be achieved if such environmentally-targeted agricultural practices were employed. Traditional approaches to water quality improvement through application of traditional BMPs will result in little or no change in nutrient export and minor decreases in sediment export from Corn Belt watersheds. (KEY TERMS: watershed management; future scenarios; agricultural watersheds; modeling; water quality; SWAT.) 1 Paper No.