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At least 1,441 records · Page 80Linked to original sources

USGS1986

Three-dimensional steady-state simulation of flow in the sand-and-gravel aquifer, southern Escambia County, Florida

The sand-and-gravel aquifer is the only freshwater aquifer in southern Escambia County, Florida and is the source of public water supply for the area, including the City of Pensacola. The aquifer was simulated by a two-layer, digital model to provide hydrologic information for water resource planning. The lower layer represents the main-producing zone; the upper layer represents all of the aquifer above the main-producing zone including an unconfined zone and discontinuous perched, confined , and confining zones. The model was designed for steady-state simulation and predicts the response of the aquifer (changes in water levels) to groundwater pumping where steady-state conditions have been reached. Input to the model includes matrices representing constant-head nodes, starting head, transmissivity of layer 1, leakance between layers 1 and 2, lateral hydraulic conductivity of layer 2, and altitude of the base layer 2. The sources of water to the model are from recharge by infiltrated precipitation (estimated from base runoff), inflow across boundaries, and induced recharge from river leakance in periods of prolonged groundwater pumping. Model output includes final head and drawdown for each layer and total values for discharge and recharge in the model area. The model was calibrated for 1972 pumping and tested by simulating pumpages during 1939-40, 1958, and 1977. Sensitivity analyses showed water levels in both layers were most sensitive to changes in the recharge matrix and least sensitive to river leakage. Suggestions for further development of the model include subdivision and expansion of the grid, assignment of storage coefficients for transient simulations, more intensive study of the stream-aquifer relations, and consideration of the effects of infiltration basins on recharge. (Author 's abstract)

Water-Resources Investigations Report↗

USGS2018

Developing a framework for evaluating tallgrass prairie reconstruction methods and management

The thousands of hectares of prairie reconstructed each year in the tallgrass prairie biome can provide a valuable resource for evaluation of seed mixes, planting methods, and post-planting management if methods used and resulting characteristics of the prairies are recorded and compiled in a publicly accessible database. The objective of this study was to evaluate the use of such data to understand the outcomes of reconstructions over a 10-year period at two U.S. Fish and Wildlife Service refuges. Variables included number of species planted, seed source (combine-harvest or combine-harvest plus hand-collected), fire history, and planting method and season. In 2015 we surveyed vegetation on 81 reconstructions and calculated proportion of planted species observed; introduced species richness; native species richness, evenness and diversity; and mean coefficient of conservatism. We conducted exploratory analyses to learn how implied communities based on seed mix compared with observed vegetation; which seeding or management variables were influential in the outcome of the reconstructions; and consistency of responses between the two refuges. Insights from this analysis include: 1) proportion of planted species observed in 2015 declined as planted richness increased, but lack of data on seeding rate per species limited conclusions about value of added species; 2) differing responses to seeding and management between the two refuges suggest the importance of geographic variability that could be addressed using a public database; and 3) variables such as fire history are difficult to quantify consistently and should be carefully evaluated in the context of a public data repository.

Ecological Restoration↗

USGS1961

Developing ground water in the central Sevier Valley, Utah

This report presents a summary of conclusions reached from the recently completed State Engineer-United States Geological Survey cooperative investigation of the geology and ground water resources of the central Sevier River Valley. The detailed report will be published as a United States Geological Survey water supply paper and will be available to the public.

Utah↗

USGS2003

Pharmaceuticals, hormones, personal-care products, and other organic wastewater contaminants in water resources: Recent research activities of the U.S. Geological Survey's toxic substances hydrology program

Recent decades have brought increasing concerns for potential contamination of water resources that could inadvertently result during production, use, and disposal of the numerous chemicals offering improvements in industry, agriculture, medical treatment, and even common household products. Increasing knowledge of the environmental occurrence or toxicological behavior of these contaminants from various studies in Europe, United States, and elsewhere has resulted in increased concern for potential adverse environmental and human health effects (Daughton and Ternes, 1999). Ecologists and public health experts often have incomplete understandings of the toxicological significance of many of these contaminants, particularly long-term, low-level exposure and when they occur in mixtures with other contaminants (Daughton and Ternes, 1999; Kümmerer, 2001). In addition, these ‘emerging contaminants’ are not typically monitored or assessed in ambient water resources. The need to understand the processes controlling the transport and fate of these contaminants in the environment, and the lack of knowledge of the significance of long-term exposures have increased the need to study environmental occurrence down to trace (nanogram per liter) levels. Furthermore, the possibility that mixtures of environmental contaminants may interact synergistically or antagonistically has increased the need to characterize the types of mixtures that are found in our waters. The U.S. Geological Survey’s Toxic Substances Hydrology Program (Toxics Program) is developing information and tools on emerging water-quality issues that will be used to design and improve water-quality monitoring and assessment programs of the USGS and others, and for proactive decision-making by industry, regulators, the research community, and the public (http://toxics.usgs.gov/regional/emc.html). This research on emerging water-quality issues includes a combination of laboratory work to develop new analytical capabilities as well as field work on the occurrence, fate, and effects of these contaminants.

Geohealth News↗

USGS1983

Ground-water resources in the Hood Basin, Oregon

The Hood Basin, an area of 1,035 square miles in north-central Oregon, includes the drainage basins of all tributaries of the Columbia River between Eagle Creek and Fifteenmile Creek. The physical characteristics and climate of the basin are diverse. The Wasco subarea, in the eastern half of the basin, has moderate relief, mostly intermittent streams, and semiarid climate. The Hood subarea, in the western half, has rugged topography, numerous perennial streams, and a humid climate. Water-bearing geologic units that underlie the basin include volcanic, volcaniclastic, and sedimentary rocks of Miocene to Holocene age, and unconsolidated surficial deposits of Pleistocene and Holocene age. The most important water-bearing unit, the Columbia River Basalt Group, underlies almost the entire basin. Total thickness probably exceeds 2,000 feet, but by 1980 only the upper 1,000 feet or less had been developed by wells. Wells in this unit generally yield from 15 to 1,000 gallons per minute and a few yield as much as 3,300 gallons per minute. The most productive aquifer in the Columbia River Basalt Group is The Dalles Ground Water Reservoir, a permeable zone of fractured basalt about 25 to 30 square miles in extent that underlies the city of The Dalles. During the late 1950's and mid-1960's, withdrawals of 15,000 acre-feet per year or more caused water levels in the aquifer to decline sharply. Pumpage had diminished to about 5,000 acre-feet per year in 1979 and water levels have stabilized, indicating that ground water recharge and discharge, including the pumping, are in balance. The other principal geologic units in the basin have more limited areal distribution and less saturated thickness than the Columbia River Basalt Group. Generally, these units are capable of yielding from a few to a hundred gallons per minute to wells. Most of the ground water in the basin is chemically suitable for domestic, irrigation, or other uses. Some ground water has objectionable concentrations of iron (0.3 to 6.4 milligrams per liter) and manganese (0.05 to 1.2 milligrams per liter) or is moderately hard to very hard (60 to 260 milligrams per liter as CaCO 3 ). The principal use of ground water in the Hood Basin is for irrigation of crops, with an estimated withdrawal of 7,700 acre-feet in 1979. Additional ground-water withdrawals in 1979 were estimated as: Industrial, 2,600 acre-feet; public supply, 2,100 acre-feet; and domestic and stock supply, 200 acre-feet.

Oregon↗

USGS2003

The influence of gender on the relationship between wildlife value orientations, beliefs, and the acceptability of lethal deer control in Cuyahoga Valley National Park

This study examines how wildlife value orientations, attitudes, and gender influence acceptance of lethal actions to control deer in Cuyahoga Valley National Park in Ohio. Data were collected from female and male residents (n = 659) in a nine-county area, the primary service area of the park. Females and males demonstrated significant differences in their wildlife value orientations, attitudes toward lethal deer control, beliefs about the outcome of lethal deer control, and perceived personal impacts of lethal deer control. Gender also acted as a moderator of the relationship between values, beliefs and attitudes. Results indicate that a focus on understanding differences between males and females is essential to public participation in decision making concerning this and similar issues.

Society and Natural Resources↗

USGS1982

Water use in Wisconsin, 1979

This report summarizes the uses of water in Wisconsin for 1979, except aesthetics, navigation, and recreational use. The greatest single use of water, an instream use, was for hydroelectric power production. About 26 trillion gallons, or 93 percent, was used for this purpose. Of the other 7 percent where water is pumped to a different location, 81 percent (6 percent of all water use) was cooling water for thermoelectric powerplants. Withdrawals of surface water and ground water by public and private systems are for residential, industrial, commercial, irrigation, and stock uses.

Wisconsin↗

USGS1985

Occurrence of natural radium-226 radioactivity in ground water of Sarasota County, Florida

Water that contains radium-226 radioactivity in excess of the 5.0-picocurie-per-liter limit set in the National Interim Primary Drinking Water Regulations was found in the majority of wells sampled throughout Sarasota County. Highest levels were found areally near the coast or near rivers and vertically in the Tamiami-upper Hawthorn aquifer where semiconsolidated phosphate pebbles occur. Analysis of data suggests that part of the radium-226 in ground water of Sarasota County is dissolved by alpha particle recoil. In slightly mineralized water, radium-226 concentrations are decreased by ion exchange or sorption. In more mineralized water, other ions compete with radium-226 for ion exchange or sorption sites. Dissolution of minerals containing radium-226 by mineralized water probably contributes a significant fraction of the dissolved radium-226. Two types of mineralized water were present in Sarasota County. One type is a marine-like water, presumably associated with saltwater encroachment in coastal areas; the other is a calcium magnesium strontium surfate bicarbonate type. In general, water that contains high radium-226 radioactivities also contains too much water hardness or dissolved solids to be used for public supply without treatment that would also reduce radium-226 radioactivities. (USGS)

Water-Resources Investigations Report↗

USGS1991

Estimated use of water in North Dakota in 1985 and trends during 1960-85

Estimates of water use in North Dakota have been compiled by the U.S. Geological Survey every 5 years since 1950. These estimates have been published in national summaries of water use (MacKichan, 1951, 1957; MacKichan and Kammerer, 1961; Murray, 1968; Murrary and Reeves, 1972, 1977; and Solley and others, 1983, 1987). In this report, estimates of offstream water use for 1985 and trends in water use in 5-year increments from 1960 through 1985 are presented for the following categories of use: Public supply Domestic and commercial Industrial and mining Thermoelectric power Agricultural (irrigation and nonirrigation)

North Dakota↗

USGS2023

Annotated bibliography of scientific research on greater sage-grouse published from October 2019 to July 2022

Integrating recent scientific knowledge into management decisions supports effective natural resource management and can lead to better resource outcomes. However, finding and accessing scientific knowledge can be time consuming and costly. To assist in this process, the U.S. Geological Survey (USGS) created a series of annotated bibliographies on topics of management concern for western lands. Previously published reports introduced a methodology for preparing annotated bibliographies to facilitate integration of recent, peer-reviewed science into resource management decisions. Therefore, relevant text from those efforts is reproduced here and built on to incorporate new information. The greater sage-grouse (Centrocercus urophasianus; hereafter “GRSG”) has been a focus of scientific investigation and management action for the past two decades. The 2015 U.S. Fish and Wildlife Service listing determination of “not warranted” under the Endangered Species Act was in part a result of a large-scale collaborative effort to develop strategies to conserve GRSG populations and their habitat and to reduce threats to both. New scientific information augments existing knowledge and can help inform updates or modifications to existing plans for managing GRSG and sagebrush ecosystems. However, the sheer number of scientific publications can be a challenge for managers tasked with evaluating and determining the need for potential updates to existing planning documents. To assist in this process, the USGS has reviewed and summarized the scientific literature published since January 1, 2015. Our most recent GRSG literature summary was published in 2020 (Carter and others, 2020) and included products published through October 2, 2019. Here, we consider products published between October 2, 2019, and July 21, 2022. We compiled and summarized peer-reviewed journal articles, data products, and formal technical reports (such as U.S. Department of Agriculture Forest Service General Technical Reports and USGS Open-File Reports) on greater sage-grouse. We first systematically searched three reference databases and three government databases using the search phrase “greater sage-grouse.” We refined the initial list of products by removing (1) duplicates, (2) publications not published as research, data products, or scientific review articles in peer-reviewed journals or as formal technical reports, and (3) products for which greater sage-grouse was not a research focus or the study did not present new data or findings about greater sage-grouse. We summarized each product using a consistent structure (background, objectives, methods, location, findings, and implications) and identified management topics addressed by each product; for example, species and population characteristics. We also identified projects that provided new geospatial data. The review process for this annotated bibliography included two initial internal colleague reviews of each summary, requesting input on each summary from an author of the original publication, and formal peer review. Our initial searches resulted in 221 total products, of which 147 met our criteria for inclusion. Across products summarized in the annotated bibliography, broad-scale habitat characteristics, behavior or demographics, site-scale habitat characteristics, habitat selection, and population estimates or targets were the most commonly addressed management topics. The online version of this bibliography, which will be available on the Science for Resource Managers tool ( https://apps.usgs.gov/science-for-resource-managers ), will be searchable by topic, location, and year, and will include links to each original publication. The studies compiled and summarized here may inform planning and management actions that seek to maintain and restore sagebrush landscapes and GRSG populations across the GRSG range.

Open-File Report↗

USGS2000

From safe yield to sustainable development of water resources - The Kansas experience

This paper presents a synthesis of water sustainability issues from the hydrologic perspective. It shows that safe yield is a flawed concept and that sustainability is an idea that is broadly used but perhaps not well understood. In general, the sustainable yield of an aquifer must be considerably less than recharge if adequate amounts of water are to be available to sustain both the quantity and quality of streams, springs, wetlands, and ground-water-dependent ecosystems. To ensure sustainability, it is imperative that water limits be established based on hydrologic principles of mass balance. To establish water-use policies and planning horizons, the transition curves of aquifer systems from ground-water storage depletion to induced recharge of surface water need to be developed. Present-day numerical models are capable of generating such transition curves. Several idealized examples of aquifer systems show how this could be done. Because of the complexity of natural systems and the uncertainties in characterizing them, the current philosophy underlying sustainable management of water resources is based on the interconnected systems approach and on adaptive management. Examples of water-resources management from Kansas illustrate some of these concepts in a real-world setting. Some of the hallmarks of Kansas water management are the formation of local ground-water management districts, the adoption of minimum streamflow standards, the use of modified safe-yield policies in some districts, the implementation of integrated resource planning by the City of Wichita, and the subbasin water-resources management program in potential problem areas. These are all appropriate steps toward sustainable development. The Kansas examples show that local decision-making is the best way to fully account for local variability in water management. However, it is imperative that public education and involvement be encouraged, so that system complexities and constraints are better understood and overly simplistic solutions avoided. (C) 2000 Elsevier Science B.V.This paper presents a synthesis of water sustainability issues from the hydrologic perspective. It shows that safe yield is a flawed concept and that sustainability is an idea that is broadly used but perhaps not well understood. In general, the sustainable yield of an aquifer must be considerably less than recharge if adequate amounts of water are to be available to sustain both the quantity and quality of streams, springs, wetlands, and ground-water-dependent ecosystems. To ensure sustainability, it is imperative that water limits be established based on hydrologic principles of mass balance. To establish water-use policies and planning horizons, the transition curves of aquifer systems from ground-water storage depletion to induced recharge of surface water need to be developed. Present-day numerical models are capable of generating such transition curves. Several idealized examples of aquifer systems show how this could be done. Because of the complexity of natural systems and the uncertainties in characterizing them, the current philosophy underlying sustainable management of water resources is based on the interconnected systems approach and on adaptive management. Examples of water-resources management from Kansas illustrate some of these concepts in a real-world setting. Some of the hallmarks of Kansas water management are the formation of local ground-water management districts, the adoption of minimum streamflow standards, the use of modified safe-yield policies in some districts, the implementation of integrated resource planning by the City of Wichita, and the subbasin water-resources management program in potential problem areas. These are all appropriate steps toward sustainable development. The Kansas examples show that local decision-making is the best way to fully account for local variability in water management. However, it is imperative that public education and involv

Journal of Hydrology↗

USGS2010

Quantifying effects of climate change on the snowmelt-dominated groundwater resources of northern New England

Recent U.S. Geological Survey (USGS) climate studies in New England have shown substantial evidence of hydrologic changes during the last 100 years, including trends toward earlier snowmelt runoff, decreasing occurrence of river ice, and decreasing winter snowpack. These studies are being expanded to include investigation of trends in groundwater levels and fluctuations. Groundwater is an important drinking-water source throughout northern New England (Maine, New Hampshire, and Vermont). The USGS is currently investigating whether or not groundwater recharge from snowmelt and precipitation exhibits historical trends. In addition to trend-testing, groundwater resources also will be analyzed by relating groundwater-level changes to the large year-to-year variability in weather conditions. Introduction The USGS has documented many seasonal climate-related changes in the northeastern United States that have occurred during the last 30 to 150 years. These changes include earlier snowmelt runoff in the late winter and early spring, decreasing duration of ice on rivers and lakes, decreasing ratio of snowfall to total precipitation, and denser and thinner late-winter snowpack. All of these changes are consistent with warming winter and spring air temperatures (Dudley and Hodgkins, 2002; Hodgkins and others, 2002; Huntington and others, 2004; Hodgkins and others, 2005; Hodgkins and Dudley, 2006a; Hodgkins and Dudley, 2006b). Climate-model projections for the Northeast indicate air-temperature warming, earlier snowmelt runoff, increases in annual evaporation, and decreased low streamflows (Hayhoe and others, 2007). The contribution and timing of spring snowmelt to groundwater recharge is particularly important to groundwater resources in the northeastern United States where aquifers typically consist of thin sediments overlying crystalline bedrock with relatively little storage capacity (Mack, 2009). Following spring recharge, groundwater slowly flows into streams throughout the summer. This groundwater flow is a source of cool water during the summer and accounts for a large proportion of the streamflow during summer low-flow periods. Groundwater is an important drinking-water source in northern New England. Approximately 32 percent of public water suppliers draw water from groundwater sources in Vermont, New Hampshire, and Maine, and approximately 40 percent of the population derives its drinking water from private wells (Kenny and others, 2009). It is vital to understand changes that may be occurring to such an important resource for planning industrial and agricultural water uses and protecting drinking water.

Fact Sheet↗

USGS2011

Water Resources of Lafayette Parish

Fresh groundwater and surface water resources are available in Lafayette Parish, which is located in south-central Louisiana. In 2005, more than 47 million gallons per day (Mgal/d) were withdrawn from water sources in Lafayette Parish. About 92 percent (43.7 Mgal/d) of withdrawals was groundwater, and 8 percent (3.6 Mgal/d) was surface water. Public-supply withdrawals accounted for nearly 49 percent (23 Mgal/d) of the total groundwater use, with the cities of Lafayette and Carencro using about 21 Mgal/d. Withdrawals for other uses included about 10.4 Mgal/d for rice irrigation and about 8.4 Mgal/d for aquaculture. Water withdrawals in Lafayette Parish increased from 33 Mgal/d in 1995 to about 47 Mgal/d in 2005. This fact sheet summarizes information on the water resources of Lafayette Parish, La. Information on groundwater and surface-water availability, quality, development, use, and trends is based on previously published reports listed in the references section.

Fact Sheet↗

USGS1984

The ground-water resources in the Ross Barnett Reservoir area, Mississippi

The Ross Barnett Reservoir area occupies about 78 sq mi of a 490 sq mi study area northeast of the City of Jackson, MS. For several years, water use in the area has increased and during 1983 about 0.57 mil gal/day were obtained from groundwater sources. Virtually all groundwater in the area is used for public supplies. The principal aquifers currently used in the area are in the Sparta Sand and Cockfield Formations. The Sparta Sand is the most intensively developed and generally the highest yielding aquifer in the study area. Water level declines have averaged 2 to 3 ft/yr since 1940. The principal source of groundwater recharge to the aquifers is precipitation on outcrops of permeable strata northeast of the area. The base of freshwater is at the base of the Meridian-upper Wilcox aquifer except in the extreme northeast part of the area where the lower Wilcox aquifer contains freshwater. Water from the aquifers is suitable for public supply use without treatment except in a few places where iron concentrations are high, at from 0.10 to 9.3 mg/L. Excessive color is also a problem in the water from some wells in the area. Color was 20 units or greater in 8 of 25 wells sampled. (Author 's abstract)

Water-Resources Investigations Report↗

USGS2021

Probabilistic methodology for the assessment of original and recoverable coal resources, illustrated with an application to a coal bed in the Fort Union Formation, Wyoming

Executive Summary The U.S. Geological Survey (USGS) has been using its Circular 891 for evaluating uncertainty in coal resource assessments for more than 35 years. Calculated cell tonnages are assigned to four qualitative reliability classes depending exclusively on distance to the nearest drill hole. The main appeal of this methodology, simplicity, is also its main drawback. Reliability may depend so marginally on distance to the nearest drill hole that, over time, it has become evident that Circular 891 is inadequate for modeling reliability and is limited by other shortcomings. The present publication describes the use of geostatistics as an approach allowing a more satisfactory performance than that which is achieved following Circular 891. Geostatistics takes advantage of partly random and partly organized fluctuations in attributes such as coal thickness, coal density, and elevation of the top of a coal bed, borrowing concepts and tools that have been standard features in statistics and risk analysis for decades. Considering that readers interested in this study may not have the background to go directly into the details of the methodology, we start by explaining geostatistical concepts and modeling techniques. The remainder of the publication is devoted to formulating the assessment methodology, applying it to data from the Fillmore Ranch coal bed in the Fort Union Formation in Wyoming, and explaining the computer software applied for performing calculations and displays. The assessment methodology has been designed to report three different forms of resources: coal in place, coal mineable by surface mining methods, and coal mineable by underground mining methods. These three types of resources are reported graphically by displaying both the magnitude and the reliability of total coal resources and resources at the cell scale. In the case of the Fillmore Ranch coal bed example, there is a 90-percent probability that the resources in place are 9.687 ± 0.383 billion short tons (bst), while the coal available for underground mining is 2.279 ± 0.160 bst, and that available for surface mining is only 0.240 ± 0.025 bst because of the steep dip to the west away from the outcrop. These magnitudes are derived from numerical probability distributions not following any specific form.

Wyoming↗

USGS2008

Geospatial Information is the Cornerstone of Effective Hazards Response

Every day there are hundreds of natural disasters world-wide. Some are dramatic, whereas others are barely noticeable. A natural disaster is commonly defined as a natural event with catastrophic consequences for living things in the vicinity. Those events include earthquakes, floods, hurricanes, landslides, tsunami, volcanoes, and wildfires. Man-made disasters are events that are caused by man either intentionally or by accident, and that directly or indirectly threaten public health and well-being. These occurrences span the spectrum from terrorist attacks to accidental oil spills. To assist in responding to natural and potential man-made disasters, the U.S. Geological Survey (USGS) has established the Geospatial Information Response Team (GIRT) (http://www.usgs.gov/emergency/). The primary purpose of the GIRT is to ensure rapid coordination and availability of geospatial information for effective response by emergency responders, and land and resource managers, and for scientific analysis. The GIRT is responsible for establishing monitoring procedures for geospatial data acquisition, processing, and archiving; discovery, access, and delivery of data; anticipating geospatial needs; and providing relevant geospatial products and services. The GIRT is focused on supporting programs, offices, other agencies, and the public in mission response to hazards. The GIRT will leverage the USGS Geospatial Liaison Network and partnerships with the Department of Homeland Security (DHS), National Geospatial-Intelligence Agency (NGA), and Northern Command (NORTHCOM) to coordinate the provisioning and deployment of USGS geospatial data, products, services, and equipment. The USGS geospatial liaisons will coordinate geospatial information sharing with State, local, and tribal governments, and ensure geospatial liaison back-up support procedures are in place. The GIRT will coordinate disposition of USGS staff in support of DHS response center activities as requested by DHS. The GIRT is a standing team that is available during all hazard events and is on high alert during the hurricane season from June through November each year. To track all of the requirements and data acquisitions processed through the team, the GIRT will use the new Emergency Request Track (ER Track) tool. Currently, the ER Track is only available to USGS personnel.

Fact Sheet↗

USGS2011

Management case study: Tampa Bay, Florida

Tampa Bay, Florida, USA, is a shallow, subtropical estuary that experienced severe cultural eutrophication between the 1940s and 1980s, a period when the human population of its watershed quadrupled. In response, citizen action led to the formation of a public- and private-sector partnership (the Tampa Bay Estuary Program), which adopted a number of management objectives to support the restoration and protection of the bay’s living resources. These included numeric chlorophyll a and water-clarity targets, as well as long-term goals addressing the spatial extent of seagrasses and other selected habitat types, to support estuarine-dependent faunal guilds. Over the past three decades, nitrogen controls involving sources such as wastewater treatment plants, stormwater conveyance systems, fertilizer manufacturing and shipping operations, and power plants have been undertaken to meet these and other management objectives. Cumulatively, these controls have resulted in a 60% reduction in annual total nitrogen (TN) loads relative to earlier worse-case (latter 1970s) conditions. As a result, annual water-clarity and chlorophyll a targets are currently met in most years, and seagrass cover measured in 2008 was the highest recorded since 1950. Factors that have contributed to the observed improvements in Tampa Bay over the past several decades include the following: (1) Development of numeric, science-based water-quality targets to meet a long-term goal of restoring seagrass acreage to 1950s levels. Empirical and mechanistic models found that annual average chlorophyll a concentrations were a primary manageable factor affecting light attenuation. The models also quantified relationships between TN loads, chlorophyll a concentrations, light attenuation, and fluctuations in seagrass cover. The availability of long-term monitoring data, and a systematic process for using the data to evaluate the effectiveness of management actions, has allowed managers to track progress and make adaptive changes when needed. (2) Citizen involvement, that is, the initial reductions in TN loads, which occurred in the late 1970s and early 1980s, was a result of state regulations that were developed in response to citizens’ call for action. Improved water clarity and better fishing and swimming conditions were identified as primary goals by citizens again in the early 1990s, and led to development of numeric water-quality targets and seagrass restoration goals. More recent citizen actions, from pet waste campaigns to support of reductions in residential fertilizer use, are important elements of the nitrogen management strategy. (3) Collaborative actions, that is, in addition to numerous other collaborative ventures that have benefitted Tampa Bay, the public/private Nitrogen Management Consortium, which includes more than 40 participating organizations, has implemented over 250 nutrient-reduction projects. These projects have addressed stormwater treatment, fertilizer manufacturing and shipping, agricultural practices, reclaimed water use, and atmospheric emissions from local power stations, providing more than 300 tons of TN load reductions since 1995. (4) State and federal regulatory programs, that is, regulatory requirements, such as state statutes and rules requiring compliance with advanced wastewater treatment standards by municipal sewerage works, have played a key role in Tampa Bay management efforts. The technical basis and implementation plan of the Tampa Bay nitrogen management strategy have been developed in cooperation with state and federal regulatory agencies, and the strategy has been recognized by them as an appropriate tool for meeting water-quality standards, including federally mandated total maximum daily loads. Subsequent management efforts have focused on maintaining and extending those improvements in Tampa Bay’s environmental resources by addressing water and sediment quality and habitat protection and restoration. Implementation of a collaborative, watershed-based management process, driven by an integrated science approach, has played a central role in supporting progress toward the achievement of science-based estuary management goals.

Florida↗

USGS2022

A biological condition gradient for Caribbean coral reefs: Part II. Numeric rules using sessile benthic organisms

The Biological Condition Gradient (BCG) is a conceptual model used to describe incremental changes in biological condition along a gradient of increasing anthropogenic stress. As coral reefs collapse globally, scientists and managers are focused on how to sustain the crucial structure and functions, and the benefits that healthy coral reef ecosystems provide for many economies and societies. We developed a numeric (quantitative) BGC model for the coral reefs of Puerto Rico and the US Virgin Islands to transparently facilitate ecologically meaningful management decisions regarding these fragile resources. Here, reef conditions range from natural, undisturbed conditions to severely altered or degraded conditions. Numeric decision rules were developed by an expert panel for scleractinian corals and other benthic assemblages using multiple attributes to apply in shallow-water tropical fore reefs with depths <30 m. The numeric model employed decision rules based on metrics (e.g., % live coral cover, coral species richness, pollution-sensitive coral species, unproductive and sediment substrates, % cover by Orbicella spp.) used to assess coral reef condition. Model confirmation showed the numeric BCG model predicted the panel’s median site ratings for 84% of the sites used to calibrate the model and 89% of independent validation sites. The numeric BCG model is suitable for adaptive management applications and supports bioassessment and criteria development. It is a robust assessment tool that could be used to establish ecosystem condition that would aid resource managers in evaluating and communicating current or changing conditions, protect water and habitat quality in areas of high biological integrity, or develop restoration goals with stakeholders and other public beneficiaries.

Ecological Indicators↗