Hydro-Geomorphic Classification and Potential Vegetation Mapping for Upper Mississippi River Bottomland Restoration (original) (raw)
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River stage response to alteration of Upper Mississippi River channels, floodplains, and watersheds
Hydrobiologia, 2010
The Upper Mississippi River System (UMRS) is a large and diverse river system that changes character along its 1,200 mile network of rivers and canals and 2.6 million acres of floodplain. It supports more than 30 million people in its watershed, a significant commercial waterway, more than a million acres of ''floodplain'' agriculture and about one-half million acres of river-floodplain managed for fish, wildlife, and recreation. Large-scale geomorphology and climate patterns largely determine the hydrologic characteristics of a nested hierarchy of UMRS river reaches. The human impacts above are also important drivers determining hydrologic characteristics within the hierarchy. Understanding the relationship among physical and chemical processes and ecological responses is critical to implement an adaptive management framework for UMRS ecosystem sustainability. Historic or contemporary data from 42 locations were used to examine changes in UMRS hydrology and to demonstrate the utility of a multiple reference condition analysis for river restoration. A multivariate mathematical framework was used to show how river stage hydrology can be characterized by the variability, predictability, seasonality, and rate of change. Large-scale ''geomorphic reaches'' have distinct hydrologic characteristics and response to development throughout the UMRS region, but within navigation pool hydrology is similar among all impounded reaches regardless of geomorphic reach. Reaches with hydrologic characteristics similar to historic reference conditions should be examined to determine whether those characteristics support desired management objectives. Water levels can be managed, within limits to support navigation and agriculture, to more closely resemble natural hydrology for the benefit of a variety of species, habitats, and ecological processes.
Wetlands, 2009
Alternating braided and meandering stream flow regimes throughout the Quaternary Period have left a subtly complex landscape of depositional features within the Mississippi Alluvial Valley (MAV). Prior to European settlement, those variations produced tremendous spatial complexity and diversity within vast forested wetlands and extensive fire-maintained prairies and savannas, with the distribution of specific plant communities largely reflecting abiotic site characteristics such as geomorphology, soils, and hydrology. Agricultural development, river engineering, flood protection, and drainage projects over the past century have destroyed most of the natural vegetation and obscured the patterns of plant community distribution. Recent studies have established hydrogeomorphic criteria for wetland classification over a large part of the MAV. Detailed, spatially explicit geomorphology and soils data are available for the entire MAV, and hydrologic mapping has been completed in many areas. Thus, even in areas that are currently in agriculture, the tools exist to adapt the hydrogeomorphic classification and to develop maps of potential plant community distribution based on abiotic characteristics of sites. These Potential Natural Vegetation maps provide an indication of the multi-scale complexity that once characterized the MAV, and serve as planning tools for ecosystem restoration.
Spatial patterns of aquatic habitat richness in the Upper Mississippi River floodplain, USA
Ecological Indicators, 2012
Interactions among hydrology and geomorphology create shifting mosaics of aquatic habitat patches in large river floodplains (e.g., main and side channels, floodplain lakes, and shallow backwater areas) and the connectivity among these habitat patches underpins high levels of biotic diversity and productivity. However, the diversity and connectivity among the habitats of most floodplain rivers have been negatively impacted by hydrologic and structural modifications that support commercial navigation and control flooding. We therefore tested the hypothesis that the rate of increase in patch richness (# of types) with increasing scale reflects anthropogenic modifications to habitat diversity and connectivity in a large floodplain river, the Upper Mississippi River (UMR). To do this, we calculated the number of aquatic habitat patch types within neighborhoods surrounding each of the ≈19 million 5-m aquatic pixels of the UMR for multiple neighborhood sizes (1-100 ha). For all of the 87 river-reach focal areas we examined, changes in habitat richness (R) with increasing neighborhood length (L, # pixels) were characterized by a fractal-like power function R = L z (R 2 > 0.92 (P < 0.05)). The scaling exponent (z) measures the rate of increase in habitat richness with neighborhood size and is related to a fractal dimension. Variation in z reflected fundamental changes to spatial patterns of aquatic habitat richness in this river system. With only a few exceptions, z exceeded the river-wide average of 0.18 in focal areas where side channels, contiguous floodplain lakes, and contiguous shallow-water areas exceeded 5%, 5%, and 10% of the floodplain respectively. In contrast, z was always less than 0.18 for focal areas where impounded water exceeded 40% of floodplain area. Our results suggest that rehabilitation efforts that target areas with <5% of the floodplain in side channels, <5% in floodplain lakes, and/or <10% in shallow-water areas could improve habitat diversity across multiple scales in the UMR.
Forest Ecology and Management, 2005
We evaluated the severe degradation of floodplain habitats resulting from channelization and concomitant excessive coarse sedimentation on the Middle Fork Forked Deer River in west Tennessee from 2000 to 2003. Land use practices have resulted in excessive sediment in the tributaries and river system eventually resulting in sand deposition on the floodplain, increased overbank flooding, a rise in the groundwater table, and ponding of upstream timber. Our objectives were to: (1) determine the composition of floodplain vegetation communities along the degraded river reach, (2) to isolate relationships among these communities, geomorphic features, and environmental variables and (3) evaluate successional changes based on current stand conditions. Vegetation communities were not specifically associated with predefined geomorphic features; nevertheless, hydrologic and geomorphic processes as a result of channelization have clearly affected vegetation communities. The presence of valley plugs and continued degradation of upstream reaches and tributaries on the impacted study reach has arrested recovery of floodplain plant communities. Historically common species like Liquidambar styraciflua L. and Quercus spp. L. were not important, with importance values (IV) less than 1, and occurred in less than 20% of forested plots, while Acer rubrum L., a disturbance-tolerant species, was the most important species on the site (IV = 78.1) and occurred in 87% of forested plots. The results of this study also indicate that channelization impacts on the Middle Fork Forked Deer River are more temporally and spatially complex than previously described for other river systems. Rehabilitation of this system necessitates a long-term, landscape-scale solution that addresses watershed rehabilitation in a spatially and temporally hierarchical manner. #
A Brief History of Flooding and Flood Control Measures Along the Mississippi River Basin
Natural Disasters and Adaptation to Climate Change, 2013
Stream and river valleys have been preferred sites for human habitation for millions of years, dating back to our earliest known ancestors in Turkana Gorge in the Great Rift Valley of Kenya (e.g. Kusky, 2008). These locations offer routes of relatively easy access through rugged mountainous terrain, provide life-sustaining drinking water for people and livestock and are invaluable for irrigation. The soils in river valleys are also some of the most fertile that can be found because they are replenished by yearly or less frequent floods. The initial wave of European settlers to America flocked to valleys carved by the Hudson, James (Virginia) and Ohio rivers. As the country grew, Americans trekked west to settle along the Mississippi, Missouri, Red and many other waterways. Urban centres sprang up along their courses, for rivers provided convenient, quicker and cheaper transportation than overland travel. But human habitation and progress have left a dark legacy. Many, if not most, of the streams and rivers are polluted because industry has discharged billions of gallons of chemical waste into the waterways. Humans themselves have shown an almost callous disregard for rivers by allowing harmful agricultural runoff laced with pesticides and herbicides or simply dumping trash and household waste into the water.
Development in the Upper Mississippi Basin: 10 years after the Great Flood of 1993
Landscape and Urban Planning, 2005
Flooding in the Upper Mississippi River Basin during the summer of 1993 caused between US$ 12 and 16 billion worth of damage. Since 1993, millions of dollars of new development have poured into the flood-impacted areas contrary to the recommendations of Interagency Floodplain Management Review Committee, among others. Tracking development has been difficult. A diverse set of regulations and land use controls have caused varying amounts of development in the Upper Mississippi River Basin, with Missouri leading the way with over 17.31 km 2 of new development. This study documents the changes in the basin affected by the 1993 floods 10 years after the event by conducting an analysis to identify new development within the 500-year floodplain and in the floodwater inundated areas. This study used Landsat satellite data to identify areas experiencing development.