Slowing runoff: A natural floodplain has surface conditions favoring local ponding and flood detention, plus subsurface conditions favoring infiltration and storage. In coastal areas, beaches, sand bars, dunes, and wetlands act as natural barriers to dissipate waves and protect back-lying areas from flooding and erosion. Vegetation also reduces shoreline erosion. One acre of floodplain flooded one foot deep holds approximately 330,000 gallons of water.įlow rate and erosion reduction: In their natural vegetated state, floodplains slow the rate at which the incoming overland flow reaches the main water body in the area. Flood storage is particularly important in urban areas where even small floods resulting from a 5- or 10-year storm can cause severe flood damage. This reduces flood peaks and velocities and the potential for erosion. Likewise, the physical characteristics of the floodplain shape flood flows and can provide flood loss reduction benefits to include the following:Įxcess water storage: Except in narrow, steep valleys and areas of coastal bluffs, floodplains provide a broad area which allows floodwaters to spread out and temporarily store excess water. Rivers and streams shape floodplain topography and influence riparian habitats and riverine ecosystems. Natural Floodplains and Flood Loss Reductionįloodplains provide numerous flood loss reduction benefits as a result of their unique natural functions. See the Green Guide, published by the Association of State Floodplain Managers, for more information on the benefits of natural systems and the history of floodplain development. Higher quality recreational opportunities (fishing, bird watching, boating, etc.).Some of the benefits of floodplains to a functioning natural system include: They also provide other benefits of considerable economic, social, and environmental value that are often overlooked when local land-use decisions are made.įloodplains frequently contain wetlands and other important ecological areas which directly affect the quality of the local environment.
In addition, more general methodological developments such as parallel transmission and motion correction will be discussed that are required to leverage the full potential of higher magnetic fields, and an overview of relevant physiological considerations of human high magnetic field exposure is provided.Natural floodplains provide flood risk reduction benefits by slowing runoff and storing flood water.
Emphasis is given to techniques that particularly benefit from the changing physical characteristics at high magnetic fields, including susceptibility-weighted imaging and phase-contrast techniques, imaging with X-nuclei, MR spectroscopy, CEST imaging, as well as functional MRI.
This review presents an overview of some of the latest methodological developments in human ultra-high field MRI/MRS as well as associated clinical and scientific applications. On the other side of the scale are gains in signal-to-noise or contrast-to-noise ratio that allow finer structures to be visualized and smaller physiological effects to be detected. Imaging human-sized objects at such high frequencies presents several challenges including non-uniform radiofrequency fields, enhanced susceptibility artifacts, and higher radiofrequency energy deposition in the tissue. In recent years, new human MR systems have become available operating at static magnetic fields of 7 T or higher (≥300 MHz proton frequency). Magnetic resonance imaging and spectroscopic techniques are widely used in humans both for clinical diagnostic applications and in basic research areas such as cognitive neuroimaging.