Open Access. Powered by Scholars. Published by Universities.®

Geography Commons™

Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1261 - 1290 of 2514

Full-Text Articles in Geography

Climate Change Adaptation For Southern California Groundwater Managers: A Case Study Of The Six Basins Aquifer, Frank Lyles Jan 2017

Climate Change Adaptation For Southern California Groundwater Managers: A Case Study Of The Six Basins Aquifer, Frank Lyles

Pomona Senior Theses

Groundwater has been very important to the economic development of Southern California, and will continue to be a crucial resource in the 21st century. However, Climate Change threatens to disrupt many of the physical and economic processes that control the flow of water in and out of aquifers. One groundwater manager, the Six Basins Watermaster in eastern Los Angeles and western San Bernardino Counties, has developed a long-term planning document called the Strategic Plan that mostly fails to address the implications of Climate Change, especially for local water supplies. This thesis presents an in-depth analysis of the Six Basin Watermaster’s …


Evaluating The Potential Of A Geospatial/Geostatistical Methodology For Locating Rain-Derived Infiltration And Inflow Into Wastewater Treatment Systems In The Minneapolis/St. Paul Metropolitan Area, Minnesota, Usa, Vinson Aaron Williams Jan 2017

Evaluating The Potential Of A Geospatial/Geostatistical Methodology For Locating Rain-Derived Infiltration And Inflow Into Wastewater Treatment Systems In The Minneapolis/St. Paul Metropolitan Area, Minnesota, Usa, Vinson Aaron Williams

All Graduate Theses, Dissertations, and Other Capstone Projects

A significant issue facing municipal wastewater treatment infrastructure (WWTI) is how to manage infiltration and inflow (I/I). I/I of rain and ground water permeate into WWTI after precipitation events, periods of groundwater table rise, and percolation from surrounding surface waters. This can create discharges above the infrastructure's flow capacity, increase costs for processing the wastewater and add undesired stress to aging wastewater networks. In an attempt to assess this problem cost and time inefficient approaches have commonly been applied. This study utilizes a new and more radical methodology to try and make WWTI management more efficient. This study applies ArcGIS …


Information Technology Approaches To Forest Management, Mary Snow, Richard Snow Jan 2017

Information Technology Approaches To Forest Management, Mary Snow, Richard Snow

Publications

The majority of the world’s forests occur where there is a dry season long enough to affect a seasonal change in the forest community. The seasonal forest may include evergreen, semi-deciduous, deciduous trees, or some combination of these. Local differences in soil or other site characteristics often determine which community persists. Since the seasonal forests exist where there is seasonal precipitation, the character of the forest is closely associated with the length of the rainy season. As the length of the rainy season decreases, the density of the canopy decreases. If the global climate system warms and prolonged drought gives …


Characterization Of Ecological Water Stress In The U.S. Great Lakes Region Using A Geospatial Modeling Approach, Sara Alian Jan 2017

Characterization Of Ecological Water Stress In The U.S. Great Lakes Region Using A Geospatial Modeling Approach, Sara Alian

Dissertations, Master's Theses and Master's Reports

Anthropocentric water resources management affects aquatic habitats by changing streamflow regime. Understanding the impacts of water withdrawal from different sources and consumption by various economic sectors at different spatial and temporal scales is key to characterizing ecologically harmful streamflow disturbances. To this end, we developed a generic, integrative framework to characterize catchment scale water stress at annual and monthly time scales. The framework accounts for spatially cumulative consumptive and non-consumptive use impacts and associated changes in flow due to depletion and return flow along the stream network. Application of the framework to the U.S. Great Lakes Region indicates that a …


Oceans Of Space, Stephanie Steinbrecher '16 Dec 2016

Oceans Of Space, Stephanie Steinbrecher '16

EnviroLab Asia

"Oceans of Space" relates my observations of the 2016 EnviroLab Asia Clinic Trip to Singapore and Sarawak, Malaysia. In this meditation, the concept of space serves as a lens to examine assumptions of geopolitical, historical, and philosophical positioning—regionally and globally. At the center of my inquiry is EnviroLab's connection to the Dayak communities in Baram, Sarawak. This region is experiencing dramatic social and ecological change as a result of industrial development. By triangulating my subjective impressions of this space, various knowledge systems, and the qualitative data EnviroLab gathered in Southeast Asia, I aim to untangle some paradoxes that complicate the …


Ironstone Gravel Types In Western Australia: Re-Purposing A Geological Survey To Improve Soil Management, Edward A. Griffin, Karen Holmes, Tim Overheu Dec 2016

Ironstone Gravel Types In Western Australia: Re-Purposing A Geological Survey To Improve Soil Management, Edward A. Griffin, Karen Holmes, Tim Overheu

Conference papers and presentations

The deeply laterised landscapes of Western Australia’s wheatbelt contain large amounts of ferruginous concretions or pisoliths, referred to locally as ironstone gravel. Soil surveys over the years have described ironstone gravel presence and abundance, and the state soil classification system recognises their importance in agriculture by designating ‘ironstone gravel soils’ at the highest level of the classification hierarchy. These gravels have generally been assumed inert in agricultural soils; however, farm trials and anecdotal experience suggest they may play a more active role in nutrient and water retention than previously recognised. Gravelly soil performance under dryland agriculture varies dramatically across the …


Mapping The Impact Of Intensive Rotational Grazing On Soil Fertility Over Time On Greenbrier Farms In Pickens County, South Carolina, Emily Kirby Dec 2016

Mapping The Impact Of Intensive Rotational Grazing On Soil Fertility Over Time On Greenbrier Farms In Pickens County, South Carolina, Emily Kirby

Earth and Environmental Sciences Presentations

Intensive rotational grazing (IRG) is a management technique that involves a more intentional management approach which includes increased paddock numbers, shorter grazing periods, larger livestock presence per acre, and longer periods of rest on pastures. Potential advantages of this management technique include improved forage quality, greater yield, decreased erosion, stable production during adverse growing condition, and improved soil fertility. This study collects and analyzes data to understand the impact of rotational grazing on soil fertility as measured by SOC (soil organic carbon) and SON (soil organic nitrogen) on Greenbrier Farms in Easley, South Carolina. This study analyzes the transition from …


The Impact Of Organic Farms: Biodiversity And Climate Change Resilience In The Southeast, Josie Newton Dec 2016

The Impact Of Organic Farms: Biodiversity And Climate Change Resilience In The Southeast, Josie Newton

Earth and Environmental Sciences Presentations

Resilience to climate change serves as an indicator of the effectiveness of organic farming practices. Resilience means that an area is able to return to a stable state after a disturbance. In this context, it means that the area is able to function regularly even in the face of climate change, an instance that affects species health and biodiversity. By mapping the locations of organic farms across the southeastern United States along with the resilience scores of areas as evaluated by The Nature Conservancy and comparing this map to farm locations and biodiversity measures, we are able to determine the …


Habitat Quality Modeling For Bird Species At Furman University, Emma Cook Dec 2016

Habitat Quality Modeling For Bird Species At Furman University, Emma Cook

Earth and Environmental Sciences Presentations

In rapidly urbanizing areas, such as Greenville County in Upstate South Carolina, it is important to study habitat use and quality across land cover types in order to maximize conservation. Habitat fragmentation is a threat to many species of birds in areas with increasing development, especially those species that utilize larger forest patches for nesting and foraging. While land cover type and patch size are extremely important factors in determining habitat quality for birds, recent research has shown that the matrix of surrounding landscape proves to be very important as well. The landscape matrix, sometimes called landscape mosaic, considers the …


Soundscape Mapping: Spatial Variability Of Sound At Furman University, Alec Schindler Dec 2016

Soundscape Mapping: Spatial Variability Of Sound At Furman University, Alec Schindler

Earth and Environmental Sciences Presentations

Looking at the entire soundscape and studying its spatial variability can often give us important information about the health of the ecosystem. However, most previous studies only measure sound intensity, and are therefore limited in their depiction of the soundscape. Another tool for mapping soundscapes is SPreAD-GIS. This tool models sound propagation in an area. However, previous studies have only used it to evaluate the effects of noise pollution, but not applied it towards depicting the soundscape as a whole. I mapped the soundscape of Furman University’s campus using sound intensity as well as many different soundscape indices in order …


Evaluating Lithology As An Erosional Control On A Fluviokarst System In Northeastern Kentucky, Andrew K. Francis Dec 2016

Evaluating Lithology As An Erosional Control On A Fluviokarst System In Northeastern Kentucky, Andrew K. Francis

Theses and Dissertations

Longitudinal stream profiles can be used to evaluate landscape evolution. Lithology as a control on a stream profile is especially of interests because fluviokarst systems are characterized by the contact of carbonate and non-carbonate rocks at the surface. Due to the difference in weathering processes between carbonates and non-carbonate rocks, it is likely that there is a difference in their rates of erosion. Cave Branch and its tributary Horn Hollow, are fluviokarst systems located in northeastern Kentucky. This area is primarily comprised of sandstone and limestone. The objectives of this study were to determine if variation in lithology was creating …


Landsat 5 Thematic Mapper Reflectance And Ndvi 27-Year Time Series Inconsistencies Due To Satellite Orbit Change, Hankui Zhang, David P. Roy Dec 2016

Landsat 5 Thematic Mapper Reflectance And Ndvi 27-Year Time Series Inconsistencies Due To Satellite Orbit Change, Hankui Zhang, David P. Roy

GSCE Faculty Publications

The Landsat 5 Thematic Mapper (TM) sensor provided the longest single mission terrestrial remote sensing data record but temporally sparse station keeping maneuvers meant that the Landsat 5 orbit changed over the 27 year mission life. Long-term Landsat 5 TM reflectance inconsistencies may be introduced by orbit change induced solar zenith variations combined with surface reflectance anisotropy, commonly described by the Bi-directional Reflectance Distribution Function (BRDF). This study quantifies the local overpass time and observed solar zenith angle changes for all the Landsat 5 TM images available at two latitudinally separated locations along the same north-south Landsat path (27) in …


Aiddata Gis International Fellowship: Ghana West-Africa, Jason N. Ready Dec 2016

Aiddata Gis International Fellowship: Ghana West-Africa, Jason N. Ready

Sustainability and Social Justice

My internship, or fellowship as it was commonly referred to, was funded by a non-profit organization out of Williamsburg Virginia called AidData. This fellowship took place in in the country of Ghana, West-Africa beginning in May of 2016 and continued for 14 weeks with 40 hours each week. The objective of this internship was to provide in-depth training on the use of geographic Information Systems to Private and Public sectors within the country to allow for increased efficiency, and transparency through data visualization. In accordance with the requirement of Clark Universities GISDE master’s program this paper will delve into the …


Quantifying Terrestrial Ecosystem Carbon Dynamics With Mechanistically-Based Biogeochemistry Models And In Situ And Remotely Sensed Data, Shaoqing Liu Dec 2016

Quantifying Terrestrial Ecosystem Carbon Dynamics With Mechanistically-Based Biogeochemistry Models And In Situ And Remotely Sensed Data, Shaoqing Liu

Open Access Dissertations

Terrestrial ecosystem plays a critical role in the global carbon cycle and climate system. Therefore, it is important to accurately quantify the carbon dynamics of terrestrial ecosystem under future climatic change condition. This dissertation evaluates the regional carbon dynamics by using upscaling approach, mechanistically-based biogeochemistry models and in situ and remotely sensed data.

The upscaling studies based on FLUXNET network has provided us the spatial and temporal pattern of the carbon fluxes but it fails to consider the atmospheric CO2 effect given its important physiological role in carbon assimilation. In the second chapter, we consider the effect of atmospheric CO2 …


Plant Community Composition And Structure Monitoring For Scotts Bluff National Monument, 2016 Data Report, Molly B. Davis, Daniel J. Swanson Dec 2016

Plant Community Composition And Structure Monitoring For Scotts Bluff National Monument, 2016 Data Report, Molly B. Davis, Daniel J. Swanson

United States National Park Service: Publications

Abstract

This report presents the results of vegetation monitoring efforts in 2016 at Scotts Bluff National Monument (SCBL) by the Northern Great Plains Inventory and Monitoring Network (NGPN) and Northern Great Plains Fire Ecology Program (NGPFire).

During the sixth full year of field work, crew members from NGPN visited eight long-term monitoring plots on May 23-25, 2016 to collect data on the plant communities at SCBL. This is part of a long-term monitoring effort to better understand the condition of the vegetation at SCBL. NGPN staff captured data relating to species richness, herb-layer height, abundance of individual native and non-native …


Plant Community Composition And Structure Monitoring For Agate Fossil Beds National Monument, 2016 Data Report, Aaron T. Rasor, Daniel J. Swanson Dec 2016

Plant Community Composition And Structure Monitoring For Agate Fossil Beds National Monument, 2016 Data Report, Aaron T. Rasor, Daniel J. Swanson

United States National Park Service: Publications

Abstract

This report presents the results of vegetation monitoring efforts in 2016 at Agate Fossil Beds National Monument (AGFO) by the Northern Great Plains Inventory and Monitoring Network (NGPN).

During the sixth full year of field work, crew members from NGPN visited six long-term plant community monitoring (PCM) plots and the Northern Great Plains Fire Effects Crew (NGPFire) visited nine fire plant community monitoring (FPCM) plots to collect data on the plant communities at AGFO. This effort is part of a long-term monitoring program established to better understand the condition of the mixed-grass prairie, riparian, and upland regions in AGFO. …


The Relationship Between Lead In Groundwater And Elementary School Students' Academic Performance In Missouri, Lynnette Xiangling Li Dec 2016

The Relationship Between Lead In Groundwater And Elementary School Students' Academic Performance In Missouri, Lynnette Xiangling Li

Graduate Theses/Dissertations

Lead exposure can come from various sources, e.g., lead mines, industrial areas, and lead based paint. Missouri has more than 4,128 lead mines. Lead is a neurotoxin. The objectives of the study were to investigate i) the spatial relationship between lead mines and lead distribution in groundwater, ii) the statistical impact of lead in groundwater on students' Missouri Assessment Program (MAP) scores, and iii) the geographic variations of lead's impact on students' MAP scores. Geographic Information Science spatial analysis tools were used to analyze the concentration of lead in groundwater within school districts in Missouri. Regression analysis was utilized to …


A Gis Approach To Modeling Groundwater Levels In The Mississippi River Valley Alluvial Aquifer, Josef Orion Lilly Dec 2016

A Gis Approach To Modeling Groundwater Levels In The Mississippi River Valley Alluvial Aquifer, Josef Orion Lilly

Graduate Theses and Dissertations

Groundwater depletion, a subject of growing concern for a significant portion of Arkansas, may lead to future economic challenges for the Arkansas Delta region. The Mississippi River Valley Alluvial Aquifer is the uppermost aquifer and features the largest groundwater capacity in the Mississippi Embayment Aquifer System. The Mississippi River Valley Alluvial Aquifer, commonly referred to as the “alluvial aquifer”, spans 53,000〖 km〗^2 underlying portions of Arkansas, Kentucky, Louisiana, Mississippi, Missouri, Illinois, and Tennessee. As the alluvial aquifer trends southward for approximately 250 miles alongside the Mississippi River, its geographical extent ranges from 50 to 125 miles wide. There is a …


A Gis Analysis Of Waulsortian-Like Mounds In The Mississippian Of Kentucky And Tennessee, Philip Roberson Nov 2016

A Gis Analysis Of Waulsortian-Like Mounds In The Mississippian Of Kentucky And Tennessee, Philip Roberson

Scholars Week

Following a mass extinction nearly 365 million years ago, bryozoans and crinoids replaced corals and stromatoporoids as the dominant framework organisms in reefs and, during the very earliest part of the Carboniferous period, they built reef-like structures that are known from Europe, North America and Africa. They are characterized by large size, a matrix of carbonate mud, and their major framework organisms.

Waulsortian-like mounds occur in geographically isolated patches in outcrop and in the subsurface of central Tennessee and Kentucky where they are associated with hydrocarbon production. These mounds have the same characteristic organisms as the European mounds and do …


Open Access Geospatial Data, Hannah Hamalainen Oct 2016

Open Access Geospatial Data, Hannah Hamalainen

Open Access Events

The landscape of open-access geospatial data is vastly growing with an abundance of open source software, websites, and datasets available to the public. How do we find and access these resources? Find out from the Geospatial Services Center.


Separability Analysis Of Sentinel-2a Multi-Spectral Instrument (Msi) Data For Burned Area Discrimination, Haiyan Huang, David P. Roy, Luigi Boschetti, Hankui Zhang, Lin Yan Dr., Sanath Sathyachandran Kumar, Jose Gomez-Dans, Jian Li Oct 2016

Separability Analysis Of Sentinel-2a Multi-Spectral Instrument (Msi) Data For Burned Area Discrimination, Haiyan Huang, David P. Roy, Luigi Boschetti, Hankui Zhang, Lin Yan Dr., Sanath Sathyachandran Kumar, Jose Gomez-Dans, Jian Li

GSCE Faculty Publications

: Biomass burning is a global phenomenon and systematic burned area mapping is of increasing importance for science and applications. With high spatial resolution and novelty in band design, the recently launched Sentinel-2A satellite provides a new opportunity for moderate spatial resolution burned area mapping. This study examines the performance of the Sentinel-2A Multi Spectral Instrument (MSI) bands and derived spectral indices to differentiate between unburned and burned areas. For this purpose, five pairs of pre-fire and post-fire top of atmosphere (TOA reflectance) and atmospherically corrected (surface reflectance) images were studied. The pixel values of locations that were unburned in …


Urban Heat Islands As Viewed By Microwave Radiometers And Thermal Time Indices, Lan H. Nguyen, Geoffrey M. Henebry Oct 2016

Urban Heat Islands As Viewed By Microwave Radiometers And Thermal Time Indices, Lan H. Nguyen, Geoffrey M. Henebry

GSCE Faculty Publications

Urban heat islands (UHIs) have been long studied using both ground-based observations of air temperature and remotely sensed thermal infrared (TIR) data. While ground-based observations lack spatial detail even in the occasional “dense” urban network, skin temperature retrievals using TIR data have lower temporal coverage due to revisit frequency, limited swath width, and cloud cover. Algorithms have recently been developed to retrieve near-surface air temperatures using microwave radiometer data, which enables characterization of UHIs in metropolitan areas, major conurbations, and global megacities at regional to continental scales using temporally denser time series than those that have been available from TIR …


Quantifying Undisturbed (Native) Lands In Eastern South Dakota: 2013, Pete Bauman, Benjamin Carlson, Tanner Butler Oct 2016

Quantifying Undisturbed (Native) Lands In Eastern South Dakota: 2013, Pete Bauman, Benjamin Carlson, Tanner Butler

Quantifying Undisturbed (Native) Lands in Eastern South Dakota: 2013

We employed simple GIS methods primarily utilizing the South Dakota Farm Service Agency’s Common Land Unit (CLU) data layers from 2013, along with 2012 US Department of Agriculture (USDA) National Agriculture Imagery Program (NAIP) county mosaic aerial imagery, to evaluate approximately 22.6 million acres of land in the 44 counties that comprise eastern South Dakota. Mapping of this total project area was done in three distinct project phases from 2014 through 2016. We utilized the CLU data layer, queried to show current and former cropland, to first identify and remove any areas with a cropping history, regardless of current land …


Coastal Groundwater Watch: A Citizen Science Project - Report No. 477, Alex Manda, Thomas Allen Oct 2016

Coastal Groundwater Watch: A Citizen Science Project - Report No. 477, Alex Manda, Thomas Allen

Political Science & Geography Faculty Publications

The goals of this study were to utilize citizen scientists in groundwater research in a coastal community where groundwater plays a large role in sustainable water resources management, and assess the extent of groundwater and marine inundation in response to future sea-level rise scenarios. A total of 7 citizen scientists participated in the study by measuring water levels from 15 groundwater monitoring wells using water level meters once a week over a 10-week period. Automated water level loggers were deployed in three of the same wells to assess the quality of the data collected by the citizen scientists. Additional water …


Aerosols Size Distribution Characteristics And Role Of Precipitation During Dust Storm Formation Over Saudi Arabia, Ashraf Farahat, Hesham El-Askary, A. Umran Dogan Oct 2016

Aerosols Size Distribution Characteristics And Role Of Precipitation During Dust Storm Formation Over Saudi Arabia, Ashraf Farahat, Hesham El-Askary, A. Umran Dogan

Mathematics, Physics, and Computer Science Faculty Articles and Research

Kingdom of Saudi Arabia and the Gulf region are frequently exposed to major dust storms and anthropogenic emissions from rapidly growing industrial activities that affect aerosols optical and physical characteristics. This paper integrates observations from space-borne sensors namely MODIS and CALIPSO, together with AERONET ground observations to examine eight years aerosols characteristics during the (March–May) season of 2003 to 2010 over Saudi Arabia. Aerosol analysis from the interdependent data assessment show comparable aerosols characteristics over the eight year period with higher aerosols mean optical depths over enhanced dust load region, (46–50°E, 25–29°N), during March–May of 2009 and 2010. The mean …


Cartographic Potential Of New Technologies: Hu:Care, William B. Moore Sep 2016

Cartographic Potential Of New Technologies: Hu:Care, William B. Moore

September 29, 2016: Adaptive Structures and Innovative Solutions

No abstract provided.


An Iterative Approach To Ground Penetrating Radar At The Maya Site Of Pacbitun, Belize, Sheldon Skaggs, Terry G. Powis, Clara R. Rucker, George Micheletti Sep 2016

An Iterative Approach To Ground Penetrating Radar At The Maya Site Of Pacbitun, Belize, Sheldon Skaggs, Terry G. Powis, Clara R. Rucker, George Micheletti

Publications and Research

Ground penetrating radar (GPR) surveys provide distinct advantages for archaeological prospection in ancient, complex, urban Maya sites, particularly where dense foliage or modern debris may preclude other remote sensing or geophysical techniques. Unidirectional GPR surveys using a 500 MHz shielded antenna were performed at the Middle Preclassic Maya site of Pacbitun, Belize. The survey in 2012 identified numerous linear and circular anomalies between 1 m and 2 m deep. Based on these anomalies, one 1 m × 4 m unit and three smaller units were excavated in 2013. These test units revealed a curved plaster surface not previously found at …


Is Only One Gps Point Position Sufficient To Locate You To The Road Network Accurately?, Hao Wu, Weiwei Sun, Baihua Zheng Sep 2016

Is Only One Gps Point Position Sufficient To Locate You To The Road Network Accurately?, Hao Wu, Weiwei Sun, Baihua Zheng

Research Collection School Of Computing and Information Systems

Locating only one GPS position to a road segment accurately is crucial to many location-based services such as mobile taxi-hailing service, geo-tagging, POI check-in, etc. This problem is challenging because of errors including the GPS errors and the digital map errors (misalignment and the same representation of bidirectional roads) and a lack of context information. To the best of our knowledge, no existing work studies this problem directly and the work to reduce GPS signal errors by considering hardware aspect is the most relevant. Consequently, this work is the first attempt to solve the problem of locating one GPS position …


Is Only One Gps Position Sufficient To Locate You To The Road Network Accurately?, Hao Wu, Weiwei Sun, Baihua Zheng Sep 2016

Is Only One Gps Position Sufficient To Locate You To The Road Network Accurately?, Hao Wu, Weiwei Sun, Baihua Zheng

Research Collection School Of Computing and Information Systems

Locating only one GPS position to a road segment accurately is crucial to many location-based services such as mobile taxihailing service, geo-tagging, POI check-in, etc. This problem is challenging because of errors including the GPS errors and the digital map errors (misalignment and the same representation of bidirectional roads) and a lack of context information. To the best of our knowledge, no existing work studies this problem directly and the work to reduce GPS signal errors by considering hardware aspect is the most relevant. Consequently, this work is the first attempt to solve the problem of locating one GPS position …


Use Of Water Indices Derived From Landsat Oli Imagery And Gis To Estimate The Hydrologic Connectivity Of Wetlands In The Tualatin River National Wildlife Refuge, Debra Sue Blackmore Aug 2016

Use Of Water Indices Derived From Landsat Oli Imagery And Gis To Estimate The Hydrologic Connectivity Of Wetlands In The Tualatin River National Wildlife Refuge, Debra Sue Blackmore

Dissertations and Theses

This study compared two remote sensing water indices: the Normalized Difference Water Index (NDWI) and the Modified NDWI (MNDWI). Both indices were calculated using publically-available data from the Landsat 8 Operational Land Imager (OLI). The research goal was to determine whether the indices are effective in locating open water and measuring surface soil moisture. To demonstrate the application of water indices, analysis was conducted for freshwater wetlands in the Tualatin River Basin in northwestern Oregon to estimate hydrologic connectivity and hydrological permanence between these wetlands and nearby water bodies. Remote sensing techniques have been used to study wetlands in recent …