Floodplain development

Floodplain Development. The stream channel itself occupies a relatively narrow area within a flood-plain. The channel is bordered by low-lying land that is called a floodway. As the distance away from the river increases, the slope of the land gradually increases and a slightly higher landscape called a floodway fringe is created. A cross-sectional profile of this floodplain would then show a channel with a floodway on one or both sides of the channel and a floodway fringe farther away from the stream. 

Two things will certainly help out in this situation. One would simply be better explanation of the flooding danger as given by the probability of certain events occurring in any year. These odds could, of course, change as floodplain development continues or decreases. The second element is simply better discussion of future weather patterns, as unpredictable as they are, that could occur on a global scale. 

In this chapter we discuss the distribution and the development of plant communities in floodplain areas, mainly of the big whitewater rivers, focusing on factors such as diversity, species composition, biomass and primary production. Based upon these factors, we also discuss the annual dynamics of bioelements stocks and their turnover through herbaceous and floodplain forest communities. Finally, we examine the implications of such nutrient dynamics and turnover for the aquatic biota. We do not address carbon and nutrient budgets, as these are thoroughly discussed in chapter 14. 

Albemaz, A, L. K. M., and J. M. Ayres. 1999. Selective logging along the Middle Solimoes river. In Varzea. Diversity, Development, and Conservation of Amazonia s Whitewater Floodplains, eds. C. Padoch, J. M. Ayres, M, Pinedo-Vasquez, and A. Henderson (The New York Botanical Garden Press, New York), pp. 135-151. 

Transport and distribution of sediments derived from Andean erosion across the cratonic landscape of Brazil have caused development of an upstream to downstream trend in geomorphic and hydrologic character of the channel-floodplain system (Mertes et al. 1996). In upstream reaches, scroll bar topography on the floodplain tends to... 

Floodplain lakes can be perturbed by direct alterations to the lakes and fringing wetlands, by changes to the river with which they are associated, and by modifications to the uplands surrounding their local catchments and to their airshed. To date, human-induced impacts on floodplain lakes appear only in limited areas within the Amazon basin. As development of agriculture, mining... 

On active floodplains of major rivers, the soil residence time can be in most cases no longer than a few hundred years. Soil profiles here exhibit stratification, buried, weakly developed horizons, and little if any measurable chemical weathering. 

Figure 2.1 Settings for calcrete development. In fluvial settings pedogenic calcretes can develop on floodplains and terraces, whereas groundwater calcretes may form in channel deposits or around the capillary fringe and upper part of the phreatic zone in more permeable parts of the floodplain. In alluvial fans paired calcretes may develop on the fans, with hydromorphic calcretes near discharge zones.

A) Horizontal beds forming a transition from floodplain deposits to a palustro-lacustrine environment and lacustrine limestones. (B) Lacustrine deposits with stromatolitic bioherms (C) Palustrine limestone with abundant root traces. (D) Lacustrine bottom-set sediments enriched in organic matter and showing thin turbiditic layers. (E) Palustrine limestone with a well developed palaeosol at the top. (F) Various types of crushed shell fragments in a lacustrine mud. (G) Lacustrine bioclastic and oolitic sand deposited near a shore. 

Palaeosols were developed in the floodplain (interval 4) (Fig. 15) and marginal lacustrine deposits (intervals 1 and 5) (Figs 3 and 5). However, only a few palaeosol horizons have survived erosion. Intra-clastic palaeosol fragments are common in the... 

Sediment-laden rivers flowing over flat terrain commonly develop extensive floodplains. At times, floodplains coalesce into broad depositional alluvial plains such as the Llanos of South America. The sediments in those deposits weather chemically. Less stable minerals in the sediment are broken down and alluvial soils develop. Eventually, only the most stable minerals such as quartz remain, and the clays are transformed into cation-deficient varieties. Sediment in such rivers, especially the sand, may go through many cycles of deposition, weathering, and erosion before it is transported out of the system. Compositionally, this sediment resembles that derived from transport-limited erosion. Elemental fractionation between the original bedrock and erosion products still occurs because of the permanent burial of some cation-rich material and the uninterrupted transport of much of the fine-grained suspended sediment out of the system (Johnsson etal., 1988 StaUard, 1985,1988). 

The Flood Protection Directive 2007/60/EC (while it was in preparation), through a cluster of projects (ACTIF) for the development and demonstration of new-generation flood forecasting methodologies which will advance the capabilities and accuracies of present forecasting systems (MUSIC, MANTISSA, FLOODRELIEF and others), and the elaboration of specific guidelines on how to use floodplains... 

Prohibit development (business and residential) within floodplain. Maintain area in a natural state as an open area or for recreational uses only... 

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