Water Stagnation

The stagnant water is water that does not move and have low levels of dissolved oxygen. It can be found in a small container such as a cup of tea or as big as a lake.

The water stagnation happens when water stops flowing . Standing water can be a significant environmental hazard .

The water can be trapped on the surface of the soil because it is saturated or because it is waterproof and there is not enough slope to drain. If there is a significant amount of organic matter and nutrients, microorganisms will grow until it runs out of all the Oxygen (dissolved in water) needed for breathing.

Malaria and dengue fever are among the main dangers of standing water, which can become a breeding ground for mosquitoes that transmit these diseases. Standing water can be dangerous to drink because it provides a better incubator that running water for many types of bacteria and parasites . The stagnant water is often contaminated with human faeces and animals , especially in deserts or other areas of little rain.

Standing water can be classified into the following basic types, although overlap:

-Stagnation in the body of water (stagnation in swamp, lake, lagoon, river, etc.) 

-Stagnation of surface and groundwater

-Stagnation of water trapped. The water can be trapped in human artifacts (discarded cans, pots, tires, excavations, ceilings, etc.), as well as in natural containers, such as hollow trunks of trees, pods of leaves, etc

Standing water can have significant negative impact, regardless of the type of roofing system. The design, installation and proper maintenance of the structures of roofing can avoid this situation and its associated problems.

The adverse effects of stagnant water are the following:

-Deformation of the structure of the Deck: The standing water can significantly increase the load on the covers of ceilings. As water accumulates, can increase the diversion of the deck, causing greater stagnation of water which could compromise the structural integrity of the cover.

-Damage to the surface of the roof: develop ice formations and move constantly with changes in temperature. This movement can "rub" roofing membrane to such an extent that substantial physical damage can occur in the membrane.

-Growth of algae and vegetation: When the water stagnates for long periods of time, is likely to grow algae and vegetation, which can cause damage to the membrane of the roofing. In addition, vegetation and other debris can clog storm drains and cause additional stalemates.

-Accumulation of dirt, debris and other contaminants in the area of stagnation: These elements can affect and damage the membrane surface.

-Low levels of dissolved oxygen: The stagnant water has low dissolved oxygen levels due to lack of agitation that would normally the exchange of gases needed to produce oxygen in the water. If there are fish in the water consumed available oxygen, oxygen levels can be low enough to kill fish, they need oxygen to survive. Fish affected by levels of oxygen depleted in stagnant water are often seen in the surface of the water, gasping for air.

-Bad odor: The stagnant water often has a bad odor that resembles eggs the decomposition or putrefaction of the vegetation. This is caused by the death of the organisms that require oxygen to decompose organic matter. Without the agencies present to consume organic matter, such as fish waste or dead plants, organic matter accumulates, breaks down and causes a bad odor.

Standing water can accelerate erosion and damage the membrane surface, and cause the failure of the roofing system. Allow even small amounts of moisture below the membrane of canopy can reduce the thermal efficiency of the insulation. What's more, the moisture intrusion can cause serious damage to the cover, insulation and the membrane, as well as in the inside of the building.

Diseases that can appear with the stagnation of water

Dengue y chikunguña

The rain water is stagnant and the overflow from streams favors the proliferation of mosquitoes, particularly Aedes aegypti mosquito vector of dengue and the chikunguna. The female mosquito reaches to deposit more than 500 eggs in any object with stored water, like tires, old toys or the Czech Republic; that is why it is important to collect well trash and maintain clean homes.

Leptospirosis 
is a disease caused by bacteria of the genus Leptospira spirochetes, is transmitted by direct contact with infected domestic animals or by indirect contagion through water contaminated by animal urine as dogs, cats, pigs, horses and rats. The symptoms are fever, headache, vomiting, chills cabezza, yellowish skin and skin rashes


Respiratory Infections 
Respiratory Infections (IRA) are a group of diseases that occur in the respiratory system, caused by different microorganisms such as viruses and bacteria, which begin suddenly and last less than two weeks. The population most affected are children under five years of age and the main symptoms are: fever, malaise, congestion and runny nose. At the same time there may be symptoms such as cough, sore throat, cough and shortness of breath.

Other diseases 
Other diseases that may recur with increase in the rainy season are the gastrointestinal tract or water-borne diarrheal diseases and some foods that are not handled hygienically. They are also infections of the skin, which are frequent when there is permanent contact with moisture, which can cause dermatitis.


Extraction of water

The water can be obtained from three potential sources: stormwater runoff (rain), surface water (rivers, lakes, ponds) and deep (wells, springs). The quantity and quality of water, accessibility, availability depending on the time of year and logistics necessary to make it reach the people are the criteria to be taken into account in deciding whether a source is adequate or not. The extraction of water according to the source may require a significant investment, such as the installation of a pump to draw water from a well, or a minimum use of technical and economic resources as in the case of some springs and surface water. Once the water, this can be put directly at the disposal of the people, or be channeled to a storage unit from which will be distributed.  
The water of very low quality (for example the water obtained from a river) must be stored to be treated. When there are many people who depend on a single source, storage and distribution to several taps can avoid "traffic jams".