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At least 1,531 records · Page 85Linked to original sources
USGS2000

Water-quality and water-level data for a freshwater tidal wetland, West Branch Canal Creek, Aberdeen Proving Ground, Maryland, October 1998-September 1999

This report presents water-quality data for ground-water and surface-water samples and water-level data collected by the U.S. Geological Survey from October 1998 through September 1999 at West Branch Canal Creek, Aberdeen Proving Ground, Maryland. The report also provides a description of the sampling and analytical methods that were used to collect and analyze the samples, and includes an evaluation of the quality-assurance data. The ground-water sampling network includes 88 wells or piezometers, including four 2-inch wells, two 4-inch wells, thirty 0.75-inch piezo-meters, and fifty-two 0.25-inch piezometers. Water levels were measured in 105 wells or piezometers. Surface-water samples were collected at five sites. Samples were collected from wells and 0.75-inch piezometers for measurement of field parameters, and analysis of inorganic and organic constituents during three sampling rounds: March, May through June, and July through August of 1999. Inorganic constituents and organic constituents were analyzed in samples collected from 0.25-inch piezometers during three sampling rounds in February through March, May, and September of 1999. Water levels were measured in October and November of 1998, and in February and May of 1999. Surface-water samples were collected between February and August of 1999 for analysis of organic constituents.

Open-File Report↗
USGS2008

Assessment of Effectiveness and Limitations of Habitat Suitability Models for Wetland Restoration

Habitat suitability index (HSI) models developed for wildlife in the Louisiana Coastal Area Comprehensive Ecosystem Restoration Plan (LCA study) have been assessed for parameter and overall model quality. The success of the suitability models from the South Florida Water Management District for The Everglades restoration project and from the Spatially Explicit Species Index Models (SESI) of the Across Trophic Level System Simulation (ATLSS) Program of Florida warranted investigation with possible application of modeling theory to the current LCA study. General HSI models developed by the U.S. Fish and Wildlife Service were also investigated. This report presents examinations of theoretical formulae and comparisons of the models, performed by using diverse hypothetical settings of hydrological/biological ecosystems to highlight weaknesses as well as strengths among the models, limited to the American alligator and selected wading bird species (great blue heron, great egret, and white ibis). Recommendations were made for the LCA study based on these assessments. An enhanced HSI model for the LCA study is proposed for the American alligator, and a new HSI model for wading birds is introduced for the LCA study. Performance comparisons of the proposed models with the other suitability models are made by using the aforementioned hypothetical settings.

Open-File Report↗
USGS2010

Multitemporal L- and C-Band synthetic aperture radar to highlight differences in water status among boreal forest and wetland systems in the Yukon Flats, Interior Alaska

Tracking landscape-scale water status in high-latitude boreal systems is indispensable to understanding the fate of stored and sequestered carbon in a climate change scenario. Spaceborne synthetic aperture radar (SAR) imagery provides critical information for water and moisture status in Alaskan boreal environments at the landscape scale. When combined with results from optical sensor analyses, a complementary picture of vegetation, biomass, and water status emerges. Whereas L-band SAR showed better inherent capacity to map water status, C-band had much more temporal coverage in this study. Analysis through the use of L- and C-band SARs combined with Landsat Enhanced Thematic Mapper Plus (ETM+) enables landscape stratification by vegetation and by seasonal and interannual hydrology. Resultant classifications are highly relevant to biogeochemistry at the landscape scale. These results enhance our understanding of ecosystem processes relevant to carbon balance and may be scaled up to inform regional carbon flux estimates and better parameterize general circulation models (GCMs).

Open-File Report↗
USGS2010

Biogeochemical processes in an urban, restored wetland of San Francisco Bay, California, 2007-2009: Methods and data for plant, sediment and water parameters

The restoration of 18 acres of historic tidal marsh at Crissy Field has had great success in terms of public outreach and visibility, but less success in terms of revegetated marsh sustainability. Native cordgrass (Spartina foliosa) has experienced dieback and has failed to recolonize following extended flooding events during unintended periodic closures of its inlet channel, which inhibits daily tidal flushing. We examined the biogeochemical impacts of these impoundment events on plant physiology and on sulfur and mercury chemistry to help the National Park Service land managers determine the relative influence of these inlet closures on marsh function. In this comparative study, we examined key pools of sulfur, mercury, and carbon compounds both during and between closure events. Further, we estimated the net hydrodynamic flux of methylmercury and total mercury to and from the marsh during a 24-hour diurnal cycle. This report documents the methods used and the data generated during the study.

California↗
USGS2012

Effects of prescribed burning on marsh-elevation change and the risk of wetland loss

Marsh-elevation change is the net effect of biophysical processes controlling inputs versus losses of soil volume. In many marshes, accumulation of organic matter is an important contributor to soil volume and vertical land building. In this study, we examined how prescribed burning, a common marsh-management practice, may affect elevation dynamics in the McFaddin National Wildlife Refuge, Texas by altering organic-matter accumulation. Experimental plots were established in a brackish marsh dominated by Spartina patens , a grass found throughout the Gulf of Mexico and Atlantic marshes. Experimental plots were subjected to burning and nutrient-addition treatments and monitored for 3.5 years (April 2005 – November 2008). Half of the plots were burned once in 2006; half of the plots were fertilized seasonally with nitrogen, phosphorus, and potassium. Before and after the burns, seasonal measurements were made of soil physicochemistry, vegetation structure, standing and fallen plant biomass, aboveground and belowground production, decomposition, and accretion and elevation change (measured with Surface Elevation Tables (SET)). Movements in different soil strata (surface, root zone, subroot zone) were evaluated to identify which processes were contributing to elevation change. Because several hurricanes occurred during the study period, we also assessed how these storms affected elevation change rates. The main findings of this study were as follows: 1. The main drivers of elevation change were accretion on the marsh surface and subsurface movement below the root zone, but the relative influence of these processes varied temporally. Prior to Hurricanes Gustav and Ike (September 2008), the main driver was subsurface movement; after the hurricane, both accretion and subsurface movement were important. 2. Prior to Hurricanes Gustav and Ike, rates of elevation gain and accretion above a marker horizon were higher in burned plots compared to nonburned plots, whereas nutrient addition had no detectable influence on elevation dynamics. 3. Burning decreased standing and fallen plant litter, reducing fuel load. Hurricanes Gustav and Ike also removed fallen litter from all plots. 4. Aboveground and belowground production rates varied annually but were unaffected by burning and nutrient treatments. 5. Decomposition (of a standard cellulose material) in upper soil layers was increased in burned plots but was unaffected by nutrient treatments. 6. Soil physicochemistry was unaffected by burning or nutrient treatments. 7. The elevation deficit (difference between rate of submergence and vertical land development) prior to hurricanes was less in burned plots (6.2 millimeters per year [mm yr -1 ]) compared to nonburned plots (7.2 mm yr -1 ). 8. Storm sediments delivered by Hurricane Ike raised elevations an average of 7.4 centimeters (cm), which countered an elevation deficit that had accrued over 11 years. Our findings provide preliminary insights into elevation dynamics occurring in brackish marshes of the Texas Chenier Plain under prescribed fire management. The results of this study indicate that prescribed burning conducted at 3- to 5-year intervals is not likely to negatively impact the long-term sustainability of S. patens -dominated brackish marshes at McFaddin National Wildlife Refuge and may offset existing elevation deficits by ≈ 1 mm yr -1 . The primary drivers of elevation change varied in time and space, leading to a more complex situation in terms of predicting how disturbances may alter elevation trajectories. The potential effect of burning on elevation change in other marshes will depend on several site-specific factors, including geomorphic/ sedimentary setting, tide range, local rate of relative sea level rise, plant species composition, additional management practices (for example, for flood control), and disturbance types and frequency (for example, hurricanes or herbivore grazing). Increasing the scope of inference would require installation of SETs in replicate marshes undergoing different prescribed fire intervals and in different geomorphic settings (with different hurricane frequencies and/or different sedimentary settings). Multiple locations along the Gulf and Atlantic coasts where prescribed fire is used as a management tool could provide the appropriate setting for these installations.

Open-File Report↗
USGS2014

Waterbird egg mercury concentrations in response to wetland restoration in south San Francisco Bay, California

The conversion of 50–90 percent of 15,100 acres of former salt evaporation ponds to tidal marsh habitat in the south San Francisco Bay, California, is planned as part of the South Bay Salt Pond Restoration Project. This large-scale habitat restoration may change the bioavailability of methylmercury. The South Bay already is known to have high methylmercury concentrations, with methylmercury concentrations in several waterbirds species more than known toxicity thresholds where avian reproduction is impaired. In this 2013 study, we continued monitoring bird egg mercury concentrations in response to the restoration of the Pond A8/A7/A5 Complex to a potential tidal marsh in the future. The restoration of the Pond A8/A7/A5 Complex began in autumn 2010, and the Pond A8 Notch was opened 5 feet (one of eight gates) to muted tidal action on June 1, 2011, and then closed in the winter. In autumn 2010, internal levees between Ponds A8, A7, and A5 were breached and water depths were substantially increased by flooding the Pond A8/A7/A5 Complex in February 2011. In June 2012, 15 feet (three of eight gates) of the Pond A8 Notch was opened, and then closed in December 2012. In June 2013, 15 feet of the Pond A8 Notch again was opened, and the Pond A8/A7/A5 Complex was a relatively deep and large pond with muted tidal action in the summer. This report synthesizes waterbird data from the 2013 breeding season, and combines it with our prior study’s data from 2010 and 2011.

California↗
USGS2017

Integrated wetland management for waterfowl and shorebirds at Mattamuskeet National Wildlife Refuge, North Carolina

Mattamuskeet National Wildlife Refuge (MNWR) offers a mix of open water, marsh, forest, and cropland habitats on 20,307 hectares in coastal North Carolina. In 1934, Federal legislation (Executive Order 6924) established MNWR to benefit wintering waterfowl and other migratory bird species. On an annual basis, the refuge staff decide how to manage 14 impoundments to benefit not only waterfowl during the nonbreeding season, but also shorebirds during fall and spring migration. In making these decisions, the challenge is to select a portfolio, or collection, of management actions for the impoundments that optimizes use by the three groups of birds while respecting budget constraints. In this study, a decision support tool was developed for these annual management decisions. Within the decision framework, there are three different management objectives: shorebird-use days during fall and spring migrations, and waterfowl-use days during the nonbreeding season. Sixteen potential management actions were identified for impoundments; each action represents a combination of hydroperiod and vegetation manipulation. Example hydroperiods include semi-permanent and seasonal drawdowns, and vegetation manipulations include mechanical-chemical treatment, burning, disking, and no action. Expert elicitation was used to build a Bayesian Belief Network (BBN) model that predicts shorebird- and waterfowl-use days for each potential management action. The BBN was parameterized for a representative impoundment, MI-9, and predictions were re-scaled for this impoundment to predict outcomes at other impoundments on the basis of size. Parameter estimates in the BBN model can be updated using observations from ongoing monitoring that is part of the Integrated Waterbird Management and Monitoring (IWMM) program. The optimal portfolio of management actions depends on the importance, that is, weights, assigned to the three objectives, as well as the budget. Five scenarios with a variety of objective weights and budgets were developed. Given the large number of possible portfolios (16 14 ), a heuristic genetic algorithm was used to identify a management action portfolio that maximized use-day objectives while respecting budget constraints. The genetic algorithm identified a portfolio of management actions for each of the five scenarios, enabling refuge staff to explore the sensitivity of their management decisions to objective weights and budget constraints. The decision framework developed here provides a transparent, defensible, and testable foundation for decision making at MNWR. The BBN model explicitly structures and parameterizes a mental model previously used by an expert to assign management actions to the impoundments. With ongoing IWMM monitoring, predictions from the model can be tested, and model parameters updated, to reflect empirical observations. This framework is intended to be a living document that can be updated to reflect changes in the decision context (for example, new objectives or constraints, or new models to compete with the current BBN model). Rather than a mandate to refuge staff, this framework is intended to be a decision support tool; tool outputs can become part of the deliberations of refuge staff when making difficult management decisions for multiple objectives.

North Carolina↗
USGS1982

Wetland hydrology and tree distribution of the Apalachicola River flood plain, Florida

The Apalachicola River in northwest Florida is part of a three-state drainage basin encompassing 50,800 square kilometers in Alabama, Georgia, and Florida. The river is formed by the confluence of the Chattahoochee and Flint Rivers at Jim Woodruff Dam from which it flows 171 kilometers to Apalachicola Bay in the Gulf of Mexico. Its average annual discharge at Chattahoochee, Florida, is 690 cubic meters per second (1958-80) with annual high flows averaging nearly 3,000 cubic meters per second. Its flood plain supports 450 square kilometers of bottom-land hardwood and tupelo-cypress forests. The Apalachicola River Quality Assessment focuses on the hydrology and productivity of the flood-plain forest. The purpose of this part of the assessment is to address river and flood-plain hydrology, floodplain tree species and forest types, and water and tree relations. Seasonal stage fluctuations in the upper river are three times greater than in the lower river. Analysis of long-term streamflow record revealed that 1958-79 average annual and monthly flows and flow durations were significantly greater than those of 1929-57, probably because of climatic changes. However, stage durations for the later period were equal to or less than those of the earlier period. Height of natural riverbank levees and the size and distribution of breaks in the levees have a major controlling effect on flood-plain hydrology. Thirty-two kilometers upstream of the bay, a flood-plain stream called the Brothers River was commonly under tidal influence during times of low flow in the 1980 water year. At the same distance upstream of the bay, the Apalachicola River was not under tidal influence during the 1980 water year. Of the 47 species of trees sampled, the five most common were wet-site species constituting 62 percent of the total basal area. In order of abundance, they were water tupelo, Ogeechee tupelo, baldcypress, Carolina ash, and swamp tupelo. Other very common species were sweet-gum, overcup oak, planertree, green ash, water hickory, sugarberry, and diamond-leaf oak. Five forest types were defined based on species predominance by basal area. Biomass increased downstream and was greatest in forests growing on permanently saturated soils. Depth of water, duration of inundation and saturation, and water-level fluctuation, but not water velocity, were very highly correlated with forest types. Most forest types dominated by tupelo and bald-cypress grew on permanently saturated soils with inundation by flood waters 50 to 90 per cent of the time, or an average of 75 to 225 consecutive days during the growing season from 1958 to 1980. Most forest types dominated by other species grew in areas that were saturated or inundated 5 to 25 percent of the time, or an average of 5 to 40 consecutive days during the growing season from 1958 to 1980. Water and tree relations varied with river location because range in water-level fluctuation and topographic relief in the flood plain diminished downstream.

Florida↗