Increasingly more developments and shopping centers invade the countryside, affecting the drainage structures and appurtenances of the surrounding areas. Generally, in undeveloped areas most of the water falling to the earth soaks into the ground, while the remainder flows over the surface into lakes, rivers and streams, or accumulates in low-level areas forming ponds. Meanwhile, in built-up areas, thousands of acres that had been soaking up rain have been made impervious to water because of buildings and paved areas. In these areas, the surface-water runoff might be two to ten times more than it was when the land was undeveloped.
In built-up areas, surface water typically falls into storm drains (catch basins) that in turn discharge into rivers and streams, but in some cases housing developments have been flooded with surface water after a heavy rain because their storm drainage facilities were inadequate for the increased water flow resulting from adjacent new housing developments. Usually, the increased runoff leads to rivers and streams swelling, although they are generally contained within their banks. After a prolonged rain, however, a river or stream can overflow its banks and flood the surrounding area. Even a small creek can become a raging, destructive torrent after an excessively heavy rain.
The area normally flooded when a river or a stream overflows is called a flood plain. In the United States, between five and 10 percent of the land is a flood plain. Most of this land is level and seems to be desirable from outward appearances, and with the scarcity of land in urban and suburban areas, builders constructed homes directly on the flood plains of streams and other waterways. These buildings are all vulnerable to flooding. Unfortunately, in many parts of the country, homeowners are not even aware that their homes were built in a flood-prone area.
To find out whether your house is located in a flood plain, check with the local town or county engineer. Federal flood insurance is available in many communities for those homes located in a flood plain, so if you are considering to buy such a home you may want to get a flood insurance as well.
The homeowner should be particularly concerned about surface runoff, as it can result in soil erosion, ponded water and water in the basement or crawl space. Soil erosion occurs whenever water flows over bare earth, loosening soil particles that get carried away by the flow. Water flows from a higher elevation to a lower elevation, forming natural drainage ways with the paths it takes. Steep banks and drainage ways are areas particularly vulnerable to erosion.
The basic measures for preventing or minimizing erosion is to have the ground covered as much as possible with growing vegetation such as grass, trees, bushes, shrubs and even weeds. If the vegetation keeps washing out, try a substitute cover such as gravel, stones or mulch. This cover is not as effective, but it will reduce the erosion. When the banks are too steep for a ground over of any kind, they must be stabilized by terracing or retaining walls. In addition, erosion can also be reduced by slowing down the water flow. For instance, if there is a concentrated surface runoff along a natural drainage way, the water can be diverted to a man-made channel or ridge that follows a level contour, thus spreading out water and slowing the flow so that the water does not scour and erode the soil.
Moreover, the effects of surface runoff can be minimized by reshaping the ground surface by terracing and/or regrading the lot into gentle slopes with diversionary ridges and swales. A swale is a depression in the ground that will intercept surface runoff and redirect it to an area where the water will not cause damage. If a house is located on a sloping lot, a swale or ridge should be made in the portion of the lot that slopes toward the house. This kind of diversion will prevent surface water from accumulating around the house. If it does not flow away from the foundation, the surface runoff might seep into the basement or crawl space.
There are many building lots with low, level areas that will tend to accumulate water after a rain or from surface runoffs. When the soil is slow-draining, as with slit and clay, the water will pond rather than soak into the ground. These ponded areas retain the water until it evaporates or eventually seeps into the ground.
The accumulated water may or may not be a problem, depending on the location of the pond. If the pond is over the leaching field of a septic system or in an area that normally has a lot of foot traffic or is used by children, corrective action is necessary. Bringing in fill and regrading the area will often do the trick. When regrading is not practical, the area can be drained by laying a line of perforated drainpipe through the affected area and directing one end of the pipe to a low spot. If conditions allow it, a concrete-block catch basin with radial spokes of perforated pipe can be installed at a low point, and water collected in the pipes and catch basin can then be redirected to another area. If there are no other low areas to which the ponded water can be redirected using a pipe with gravity flow, the water can be directed to a sump pit or sump pump well and pumped to the desired location.
Drainage Facility Improvements and Maintenance
Generally, issues like drainage system maintenance come to notice only when there occurs a pipe bursting, damage to the drainage lining or any other problem with the drainage structures and appurtenances. To avoid such problems, homeowners are advised to have a regular drainage inspection to assure that everything is working properly.
Drainage contractors can offer quick solutions to drainage problems, and their services include emergency drain clearing, planned maintenance, drainage facility improvements, drain replacement, cctv drain surveys, drain repairs root removal, pump stations and other services related to drainage structures. In addition, some of the major drain contractors will also offer waste water services that include investigation work, maintenance work and rehabilitation work.
Drainage problems can be a nightmare to fix and cost a fortune, so it is essential to hire a professional to periodically inspect your system and perform defect and maintenance work whenever necessary. Drain installation should be handled only by the service providers equipped with skilled engineers making use of advanced techniques.
The most common problems that occur in major industrial areas are damage to the pipes or blocked drain, often due to improper drainage maintenance. However, there are also many cases in which property developers and manufacturers complain about the improper drains leading through their property, destroying it instead of draining away from the foundation. Seek a professional drainage contractor with good recommendations and extensive experience in the field and don’t forget to periodically inspect your drainage structures and appurtenances in order to avoid costly repairs or replacements.