Environmental & Social Management Framework - About ...

More documents

Recommendations

Info

Environmental and Social Management Frameworkroads. There are other examples of apparently sustainable forest managementalong some mountain roads, particularly the extraction of Pine resin on the farwestern roads as far north as Darchula, and the numerous forest products(firewood, poles, bamboo, and cardamom) produced along the Mechi highway.One of the most common changes of land-use found on new roads is thedevelopment of bazaars (market centres) in specific areas. These tend to occur onrelatively stable sites, and thereby frequently occupy agriculture land. This oftengives rise to localized land price boom and allow development of centre of localeconomic importance. Due to this, small areas of good agriculture land areirreversibly lost.[Source: Briefing Paper on Environmental Issues and Environmental Assessment in Road Sector,RAP, 1999]c. Landslides, Slope Destabilization and Soil ErosionSoil is an important component of the natural environment, and is primarymedium for many biological and human activities, including agriculture. Instablesoils, landslides and severe erosion and, to lesser extent, earthquakes and flushfloods, are the major environmental drawbacks associated with most roadconstruction in Nepal. Consequences of landslides and soil erosion not onlyaffect the safety and serviceability condition of roads but also have chain effectson the farmers (loss of crops or farmland), land (degradation due to silt/debrisdeposition), water (degradation of quality), river and streams (change in regime),vegetation (loss and impact) and on other infrastructures like reservoirs (silting).Fisher folk may loose the basis of theirlivelihood because of sedimentation and oxygendepletion in rivers and lakes, road users beingexposed to hazardous terrain and delayed whenroad embankments or structures collapse.Slope stability can be upset by creation of roadcuts or embankments. Excessive steepness ofcut slopes, deficiency of drainage, altered andconcentrated water flows, and excessive slopeloading from spoil disposal can result inlandslides. Consequences of landslides and soilerosion not only affect the safety andserviceability condition of roads but also havechain effects on the farmers (loss of crops orfarmland), land (degradation due to silt/debrisdeposition), water (degradation of quality), riverand streams (change in regime), vegetation(loss and impact) and on other infrastructureslike reservoirs (silting). The degree of slopeinstability increases during the road constructionand offer regular sliding during later operationalphase as well. Further, it creates a number ofpartly significant risks for the down hill and/ordownstream settlements.Destabilization of SlopesDisturbance during construction (vibration, spoil disposal, borrow and quarryareas operation, slope cutting and exposed surface, construction carried out inrainy season without proper water control and drainage facilities etc.) can upsetthe often delicate balance between stabilizing factors, such as vegetation andothers which seek to destabilize, such as running water. Sometimes, cumulativeresult of all these may have impacts far beyond the road itself, affecting slopes,Chapter 4-8 April 2007
Environmental and Social Management Frameworkstreams, rivers, and dams at some distance from the initial impact. Fresh cuts areoften vulnerable to wind and rain, instigating erosion. Similarly, haphazarddisposal of construction spoils, unsuitable locations of quarry sites and borrowpits, fresh quarrying and borrowing activities, construction carried out in rainyseason without proper water control and drainage facilities; and improperconstruction methods which leave soils exposed unnecessarily, etc. are alsoreason for erosion and possible consecutive landslides. The consequences oflandslides and soil erosion not only affect the safety and serviceability conditionof roads but also have chain effects on the farmers (loss of crops or farmland),land (degradation due to silt/debris deposition), water (degradation of quality),river and streams (change in regime), vegetation (loss and impact) and on otherinfrastructures like reservoirs (silting). The costs of correcting these problems areoften many times greater than the costs of simple preventive measures.The problem of road-associated landslides generally results from interactionbetween water flow and soil, both of which are disturbed by road construction.The situation gets worse if vegetation is also cleared. Improperly disposedconstruction spoil may worsen this situation. Fresh cut slopes and embankmentsare relatively more vulnerable to landslides and soil erosion, particularly due toimproper water management in the vicinity. During the construction period,instability, landslides and soil erosion problems may result because of:• steeper cut and fill (embankment) slopes and their construction qualities• environmentally hazardous disposal of construction spoils (e.g. near waterbodies or drinking water sources, wetlands, karstic landscapes, sensitivehabitats);• unsuitable locations of quarry sites and borrow pits (eventually leading touncontrolled, unaesthetic and hazardous dump sites and mosquito breedinggrounds)• rash quarrying and borrowing activities• construction carried out in rainy season without proper water control anddrainage facilities; and• improper construction methods which leave soils exposed unnecessarily, etc.During the operational phase the instability, landslides and soil erosion result notonly from the road and its structures but also from heavy rainfall, seismicactivities and from general vehicle movement on the road. Common problemsassociated with slope failures are:- blockage or deficiency drainage structures,- modification of water paths leading to concentrated flows (mayalso be caused by blocked ditches),- high gradient in cut or fill slopes, and- cleared areas which have been left without re-plantation or otherappropriate rehabilitation measures.d. Hazards due to Spoil DisposalIn hills and mountains, large amounts of spoil can be generated during roadconstruction. Sometimes it is difficult to keep balance between cut and fill, andhaulage to disposal site will be expensive. Thus, spoils are often side-tipped,which invites most hazardous environmental and social impacts. Suchconstruction practices overload instable slope areas triggering slides, causevaluable soil erosion, destroy vegetation, cause hazard to settlement at downhillside, disrupt natural drainages and pollute water sources etc.April 2007 Chapter 4-9
Page 2 and 3:
Government of NepalMinistry of Phys
Page 4 and 5:
TABLE OF CONTENTSEnvironmental & So
Page 6 and 7:
Environmental & Social Management F
Page 8 and 9:
Page 10 and 11:
Page 12 and 13:
Page 14:
Environmental and Social Management
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40: Environmental and Social Management
Page 89: Environmental and Social Management
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
show all

Environmental & Social Management Framework - About ...

Create successful ePaper yourself

Delete template?

Save as template?