Flooding control

As in the case of highways, considerable contention results from public maintenance of the inland waterways for recreation, flood control, and other purposes, as well as for the transportation of barges and other freight-carrying vessels. Because barge transportation of chemicals is considered essential to economical distribution, governmental toUs assessed for such maintenance ate of critical interest to the chemicals industry. 

The United States and Canada sign the Columbia River Treaty. Under the treaty, Canada builds two storage dams and one dam for generation, resulting in greater power and flood control benefits at U.S. facilities downstream. 

China, the Colorado in the United States, and the Nile in Africa, are only some of the most famous examples. The construction of dams along these rivers allows flood control, and water for irrigation and power, but the retention of sediment behind the dams severely impacts some of the richest and most productive ecosystems in the world. 

Flood control dikes (or embankment), levees, and floodwalls are the most common flood protection structures. They are used in areas subject to inundation from tidal flow or riverine flooding, but not for areas directly within open floodways. Levees create a barrier to confine floodwaters to a flood-way and to protect structures behind the barrier. Floodwalls perform much the same function as levees, but are constructed from concrete. 

Funds for water retention systems, flood control, Irwestmentsln alternative irrgatlon techniques... 

The main economic use of the Ebro River has been hydropower and irrigation. The Ebro River has 187 reservoirs impounding 57% of the mean annual runoff. Such a large number of reservoirs deeply alter the fluvial regimes. None of the major dams in the basin was built for flood control, but the sheer volume of the impoundments affects the flood magnitude. Diverted water is used mainly for hydropower production and for irrigation. All the dams were constructed during the twentieth century,... 

The Ramsar site and the important bird area Lonjsko Polje Nature Park (510 km2) represent mainly palustrine-riverine wetlands located within the flood-plains of the Middle Sava river basin (Central Posavina, Croatia). It represents the largest maintained inundation area of all the Danube River catchment and, at the same time, the key facility of the flood control system of the entire Sava river basin (including Bosnia and Herzegovina, and Serbia and Montenegro). 

The series of active recovery wells located in the southeast portion of the main refinery has formed an elongated trough and a closed depression exhibiting about 2 ft of relief. A relatively steep gradient equal to almost 45 ft/mile is present between the flood control channel and the recovery wells beneath the eastern portion of this facility. 

Dams and reservoirs have been built in the last 100 years in vast numbers throughout many mountain areas. They serve different purposes, mainly irrigation, hydropower, water supply or flood control, or they aim at pursuing multipurpose functions. Effects on flow regime, for example shifts in summer and winter patterns, on sediment dynamics, and on other features of the aquatic ecosystems can be dramatic (cf. Sects. 2.2 in [11], this volume, 2 in [15], this volume). 

The authors acknowledge with appreciation the assistance of N. H. Crawford and R. K. Linsley in the use of the Stanford watershed model computer program. Assistance and data for this study were also provided by the Santa Clara County Flood Control and Water District, the San Jose Water Works, and the U. S. Geological Survey in Menlo Park. 

The principal types of open channels are natural streams or rivers artificial canals and sewers, tunnels, or pipelines not completely filled. Artificial canals may be built to convey water for purposes of water power development, irrigation or city water supply, drainage or flood control, and numerous others. While there are examples of open channels carrying liquids other than water, there exist few experimental data for such, and the numerical coefficients given here apply only to water at natural temperatures. 

From 1943 through 1971 the precipitation at the Lake Arrowhead Fire District station about 1 mile ENE of the study area averaged 40.04 inches (January-December). The standard deviation of 18.05 was exceeded five times below and five times above the mean. The 1870—1970 average estimated from isohyetals (San Bernardino County Flood Control Agency map) is between 35 and 40 inches. A dry trend continued without interruption from 1959 through 1964 with precipitation averaging 11.21 inches below the 1943-1971 average. Since 1964 the annual precipitation was 1965, 67.19 1966, 38.01 1967, 55.87 1968, 20.06 1969, 98.54 1970, 34.61 and 1971, 33.80. 

There are approximately 75 multipurpose storage reservoirs and another 75 river lock and dam structures which are operated by the division. In their operation, the highest priority is given to safety of the structures followed closely by either flood control or river navigation. Depending on the particular project, several competing purposes govern most of the day-to-day operations. 

Todd D. K. (1989) Sources of Saline Intrusion in the 400foot Aquifer, Castroville Area, California. Report for Monterey County Flood Control and Water Conservation District Salinas, CA, 41p. 

There are about 1200 hydroelectric power plants in Sweden and several thousands of other water reservoirs for other purposes. World wide there are about 45 000 large dams in the world, the vast majority of which were constructed after 1950 and in total there are several millions of smaller ponds. These dams produce several benefits including supply of irrigation water, hydropower generation, flood control, recreation, fishing and others. 

The larger, the more capital-intensive, and the more centralized the schemes, the greater their appeal in terms of power and patronage. For a critique of flood-control projects and World Bank projects in this context, see James K. Boyce, Birth of a Megaproject Political Economy of Flood Control in Bangladesh, Environmental Management 14, no. 4 (1990) 419-28. 

Avoided Cost (AC) Services allow society to avoid costs that would have been incurred in the absence of those services flood control avoids property damages, or waste treatment by wetlands avoids health costs. 

Over the last few hundred years there has been large-scale loss of wetland environments in rivers and estuaries throughout the world due to development pressures and flood control measures. The continued loss of wetlands removes valuable ecological habitats and also reduces the capacity for both carbon storage and nutrient removal by the processes described above. In the Humber estuary (UK), more than 90% of the intertidal marshes and supratidal wetlands have been lost to land reclamation over the last 300 years or so, resulting in a 99% reduc-... 

Besides the pressures mentioned in Table 3.2.2, aspects that cannot be steered directly (like climate change) and drivers (like shipping traffic, maintenance of flood control dams, fishery, etc. see Policy Summary on Pressures and Impact Analysis (2002) also influence the ecological quality of water bodies. These aspects have been considered indirectly in die pressures corresponding to the Driver, Pressure, State, Impact and Response (DPSIR) framework mentioned in the WFD CIS Guidance document on analysis of pressures and impacts (WFD, 2002). 

In Europe, pollution from agriculture and hydraulic engineering (e.g. for navigation, water supply, hydroelectricity and flood control) are seen as the two main factors inhibiting the achievement of good ecological status of European river basins (Menedez et al., 2006). In addition, water is both an input to many industrial production processes and a sink for their pollutants and wastewater, while households also consume water and cause pollution with hazardous substances. Furthermore, other economic sectors... 

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