For many years, it was believed that the occurrence of surface runoff was primarily controlled by the infiltration characteristics of the ground; whenever the rainfall rate exceeds or surpasses the soil's infiltration capacity, runoff is generated. Horton (1933, 1940) was responsible for some of the early foundational work for this concept and hence the process is referred to as Hortonian runoff. Horton (1943) also recognized that surface runoff rarely occurs on soils well protected by forest cover due to “somewhat unusual conditions”.
The term “unusual condition” can be referred to as the first concept applied for variable saturated areas in a watershed. Subsequently Hoover and Hursh (1943) and Hursh (1944) described a “dynamic form of subsurface flow” contributing to storm flow generation in forest lands while Roessel (1950) emphasized the importance of sub surface flow and groundwater changes in streamside outflow. Cappus (1960) provided clear field evidence of subsurface storm flow within the context of the variable source areaVSA concept. Based on the study of sandy soil dominated
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(2003) suggested that hillsides with mild slopes, concave topography, low-saturated hydraulic conductivity and high-shallow water table have high propensity for VSAs as compared to steep slope hillsides. Pilgrim et al. (1978); Jordan (1994); Perrin et al. (2001); Wetzel (2003); Godsey et al. (2004) reported that the spatial heterogeneity of the landscape may allow infiltration excess and saturation excess runoff generating mechanisms to be present simultaneously in a watershed. However Scherrer et al. (2007) suggested that depending on the hydrologic characteristics of a watershed, one or more of these mechanisms often dominates. Buda et al. 2009 demonstrated the influence of subsurface soil properties on surface runoff generation in agricultural watersheds with VSA hydrology which could be useful for improving the accuracy of existing VSA prediction
A major flood on any river is both a long-term and a short-term event, particularly any river basin where human influence has exerted "control" over the ri...
In the chapter the “Rainy River” of the novel The Things They Carried by Tim O’Brien, O’Brien conveys a deep moral conflict between fleeing the war to go to Canada versus staying and fighting in a war that he does not support. O’Brien is an educated man, a full time law student at Harvard and a liberal person who sees war as a pointless activity for dimwitted, war hungry men. His status makes him naive to the fact that he will be drafted into the war and thus when he receives his draft notice, he is shocked. Furthermore, his anti-war sentiments are thoroughly projected, and he unravels into a moral dilemma between finding freedom in Canada or standing his ground and fighting. An image of a rainy river marking the border between Minnesota and Canada is representative of this chapter because it reflects O’Brien’s moral division between finding freedom in Canada or standing his ground and fighting in the Vietnam war.
The hydrologic or water cycle is an important topic in geology that is tied to the weather and the formation of landforms. It is the stages of water on Earth as it transforms itself from liquid to gas to solid or liquid again (American Water Works Association, 2002). Discussed below are the hydrologic cycle and two different examples of it on Earth. One example is of Panama, which is a tropical climate. The other is of the Mojave Desert in California, which is a desert climate. These two very different climates demonstrate the hydrologic cycle in practical terms.
There are numerous stages that take place simultaneously in the hydrologic cycle and this includes evaporation. This is when the water alters from a liquid state into a gas. The damp air from the water rises into the atmosphere and when it cools, the vapor condenses and shapes into clouds. But those billows are not the only form the vapors make; it can also materialize as dew, fog and mist, which blanket the Earth, characteristically on a rainy or humid day. Evaporation takes place when water changes from a liquid state into a gaseous state, and ascents out of the pores of the earth and into the atmosphere as a vapor (“How”). While evaporation is taking place, condensation is also occurring. When the temperature in the air plunges, the clouds become heavy and as a result they relieve themselves of the extra weight, which is called precipitation. This produces rain, hail, snow and sleet, conditioned upon the temperate. As the precipitation falls, it enters the surface of the ground and percolates into the soil, which is called infiltration. The more porous the land is, the more the infiltration can take place. However, the ground cannot hold all of that water and floods. The excess rainfall, which is also called runoff that has not been absorbed makes its way into bodies of water, such as small ponds, rivers, lakes and parts of the ocean (“Summary”).
Rannie, W. F., 1998. The Red River flood in Manitoba, Canada. Prairie Perspectives: Geofraphical Essays, 1-24.
A river or “stream, ribbons of water confined to channels, or troughs, cut into the land,” (Marshak, 2009) is formed from a drainage network or “the array of interconnecting streams” that form tributaries. (Marshak, 2009). The amount of water that flows down a stream is its discharge. The discharge measurement takes the width and depths or cross sectional area of a river as well as the downstream velocity to get a numeric value for amount of water moving down stream. (Marshak, 2009)
How does the vegetation surface type affect the amount of runoff? Speculate why this happens.
“10–15 percent of US water is used for cropland.” (Marlow, Hayes, Soret, carter, Schwab, Sabate 1699)
Because watersheds are specified by natural hydrology they represent the most logical basis for managing water resources. The resource becomes the center point and managers are able to gain a more complete understanding of overall conditions in an area
The GUESS model for soil erosion, which was developed by Rose et al. (1983) illustrated the processes of soil erosion, transportation and deposition along hillside. Therefore the model can be used to predict on- and off-site effects. Soil erosion at any position on the slope and at any time during the storm is related to a sediment flux. It depends on the sediment concentration and the hydrological conditions.
The knowledge of “what is where” is pivotal to in conducting the screening, scoping and baselines studies while on the other hand data on the existing spatial patterns can help in developing an understanding of the baseline conditions as well as in impact prediction and mitigation. For instance the location of a wetland near to the proposed project site can identify impacts to do with effluent discharge while the impact of the effluent can be determined by the wetland’s ability to self purify which depends on the soil type as well as flo...
There are many types of pollution. The main types of pollution are water, air, soil, thermal, radioactive, noise, and light. The topic for this experiment is Water Pollution. Water Pollution became a problem in the 1900’s when water started being treated like sewage. Earth Day was founded by United States Senator Gaylord Nelson on April 22, 1970 because of 1900’s pollution. Water Pollution also affects humans and animals. There was a Cholera outbreak in 1854, before water pollution became a problem, and a Typhoid outbreak in New York from 1900 to 1915. There are multiple possible causes to Water Pollution. Humans let out chemicals into the environment, and when some of those chemicals
Wastewater is the combination of water-carried or liquid wastes starting in the sanitary conveniences of dwellings, industrial or commercial facilities. In addition to this, surface water, groundwater and storm water may also be present. It is any water that has been badly affected in quality by anthropogenic influence. It contains waste from residential, industrial and commercial processes. Municipal water contains industrial wastewater, sewage and gray water. Gray water is the water from sinks and showers. Large industries also produce wastewater.
Wetlands act as natural sponges that trap and slowly release surface water over time. This ability impedes on the water’s momentum and erosive potential, reducing floods, and allowing for ground water recharge. A one acre wetland can hold about 1 million gallons of water. A small wetland may not be able to store 1 million gallons, but a collection of multiple small wetlands can collect a significant amount of water. Even if a wetland can store a lot of water, the flood control depends on the type of wetland and soil quality. It has been recorded that some wetlands could store up to 50 days of flooding, but with the recent depletion of wetland size capacity may be about 8-10 days of flooding. For southern state, it is imperative to have quality wetlands as hurricanes and tsunamis are much more prevalent. Typically, states like Louisiana use stopbanks, levees, and resevoirs to protect against flo...
The Causes of Water Pollution Water pollution is very harmful to the environment and living things. Water pollution can come from many different sources. If the pollution comes from only one source, such as an oil spill, it is called point-source pollution. If it comes from many different sources, it is called nonpoint-source pollution. Most water pollution affects the immediate area surrounding the source, but there are some types of pollution, such as hazardous, that can affect areas miles away from the source.