Annex XI

Impact Mitigation Measures

Annex XI

IMPACT MITIGATION MEASURES

The best way of impact mitigation is to prevent the event occurring. All efforts should be made to locate the developmental activities in an area free of agricultural lands, cyclones earthquakes, ecologically sensitive, erosion, forests, flooding, human settlements, land slides, natural scenic beauty, water logging. In case this is not feasible the next step is to look at the raw materials/technologies/ processes alternatives which produce least impact i.e. adopting or using processes or technologies which are efficient and produce recyclable wastes/minimum waste/wastes that can be easily disposed, without affecting the environment. However if the developmental activity produce the adverse impact action has to be taken to mitigate the same. Following are some of the methods available.

Air

§ Attenuation of pollution on pathway or protection of receptor through green belts.

§ Particulate removal devices such as: cyclones, setting chambers, , scrubbers, electrostatic precipitators, and bag houses

§ Gas removal devices using absorption (liquid as a media), adsorption (molecular sieve), and catalytic converters

§ Uses of protected, controlled environment, such as oxygen masks, Houston Astrodome, etc.

§ Control of stationary source emission (including evaporation, incineration, absorption, condensation, and material substitution)

§ Use of masks

§ Dilution of odourant (dilution can change the nature as well as strength of an odour)

§ Odour counteraction or neutralise (Certain pairs of odours in appropriate concentrations may neutralise each other)

§ Odour masking or blanketing (certain weaker malodours may be suppressed by a considerably stronger good odour).

Noise

· The mitigation measures may include damping, absorption, dissipation, and deflection methods. Common techniques involve constructing sound enclosures, applying mufflers, mounting noise sources on isolators, and/or using materials with damping properties.

· Performance specifications for noise represent a way to insure the procured item is controlled.

· Ear protective devices should be used. When an individual is exposed to steady noise levels above 85-dB (A), in spite of the efforts made to reduce noise level at the source, hearing conservation measures should be initiated.

Water

· Conjunctive use of ground/surface water, to prevent flooding/water logging/depletion of water resources. Included are land use pattern, land filling, lagoon/reservoir/garland canal construction, and rainwater harvesting and pumping rate.

· Minimise flow variation from the mean flow

· Segregation of different types of wastes

· Storing of oil wastes in lagoons should be minimised in order to avoid possible contamination of the ground water system.

· Surface runoff from oil handling areas should be treated for oil separation before discharge into the environment. If oil wastes are combined with sanitary sewage, oil separation will be necessary at the wastewater treatment facility.

· All effluents containing acid/alkali/organic/toxic wastes should be processed by treatment methods. The treatment methods may include biological or chemical processes.

· The impact due to suspended solids may be minimised by controlling discharge of wastes that contain suspended solids; this includes sanitary sewage and industrial wastes. Also, all activity that increases erosion or contributes nutrients to water (thus stimulating alga growth) should be minimised.

· For wastes containing high TDS treatment methods include removal of liquid and disposal of residue by controlled land filling to avoid any possible leaching of the fills. All surface runoffs around mines or quarries should be collected treated and disposed.

· Cooling towers can be used to convert once-through systems into closed systems. Treated wastewater (such as sewage, industrial wastes, or stored surface runoffs) can be used as cooling water makeup. Chromium may be recovered from cooling tower blow down before treatment and disposal of tower blow down. . Cooling water can be processed or stored in artificial ponds until the difference in temperature between it and the receiving water is nearly equal

· Waste-containing radioactivity should be treated separately by means of de-watering procedures, and solids or brine should be disposed of with special care.

Land

· The environmental impact of soil erosion can best be mitigated by removing vegetative cover only from the specific site on which construction is to take place and by disturbing the vegetation in adjacent areas as little as possible. Land clearing activities should be kept to the absolute minimum and use crushed stone rather than asphalt or concrete for surfacing parking areas should be attempted.

· Disturbing the existing vegetation and natural contour of the land as little as possible can mitigate increases in surface runoff. Vegetation along watercourses should not be cleared indiscriminately. Neither should potholes or swamps be drained unless absolutely necessary for successful completion of the activity.

· Construction, land management, or mining activities that result in the soil being laid bare could be scheduled in such a way that some type of vegetative cover appropriate to the site could be established prior to the onset of intense rain or windstorms. If grass is to be seeded, mulch of straw will help to protect the soil from less extreme erosive forces until vegetative and root development begins.

· Natural drainage patterns can often be maintained by preparing sodden waterways or installing culverts.

· Steep slopes can be terraced, thereby effectively reducing the length of slope.

· Check dams built near construction sites can reduce the quantity of eroded soil particles reaching free-flowing streams or lakes.

· Use of “floating” foundations and height restrictions in earthquake zones and increased foundation height, wall strength, and roof support in areas periodically subject to cyclones can reduce the hazards.

· All forms of temporary structures should be avoided from the flood plain, and all permanent structures should be raised to a height above the level which flood waters can be expected to reach once every 100 years (100-year flood).

· Installation of underground drainage structures helps to reduce sediment loads

· Engineering plans can be drawn to reduce the area of earth cuts on fills below what might otherwise be acceptable, provide physical support for exposed soil or rock faces, concentrate or distribute – as appropriate the weight loading of foundations to areas or state better able to support that weight,

· use small charges for mining/blasting,

· restricting the number, frequency and area of movement of heavy machinery

· Compatibility between adjacent land uses can best be assured by providing a green belt between the proposed activity and nearby properties where any significant degree of incompatibility is likely to result.

Ecology

· Intruding as little as possible on their habitat can best mitigate the impact of activities on animals. If such animals use the area where the activity will take place, the activity should be concentrated to the maximum extent possible in those parts of the area that they least often frequent.

· During the planning phase of an activity, an attempt should be made to avoid extending into the home range wild animals. If this is not feasible, the activity should be completed, as quickly as possible, and regular and sustained use of the area over time should be minimised.

· Regular or sustained intrusions of men or equipment into nesting areas of birds should be avoided to the maximum possible extent, especially while eggs are being incubated by the adults and until the young have left the nest. The sanitation cuttings of non-commercial individual trees should destroy no known nests.

· Restricting the input of polluting substances into watercourses, estuaries, and the open sea can mitigate Impacts upon fish and shellfish populations. Additionally, when a part of the activity involves water level control, changes in such levels should be programmed to the extent it is possible to do so in a way that will minimally disturb nesting and feeding habitat.

Socio-economic Aspects

· Including, in the proposed activity funds, a welfare plan that would permit assistance for those people who would be impacted might reduce some adverse impacts. For example, when a number of jobs are to be disbanded, a service could be set up in which those people who would be without jobs could obtain assistance in locating jobs in other areas.

· In problems caused by relocation, effective rehabilitation and resettlement schemes may be drawn.