EXPERINCE SHARING ON UNDERSTANDING OF ROADSIDE DRAINAGES THEIR

EXPERINCE SHARING ON UNDERSTANDING OF ROADSIDE DRAINAGES & THEIR IMPACTS Kinzang Wangchuk Dy. Executive Engineer ORIO-RGOB Project July 23, 2018

PRESENTATION OUTLINES 1. Overview 2. 3. 4. 5. 6. understanding of Water movement. Types of drainages Choices of Drain configuration in road works Practices in Do. R Impacts of road side drainages to the road and public properties Conclusions and Recommendations

PRESENTATION OUTLINES 1. Overview Watersheds • • • understanding of Global water source Country’s watershed & dendritic pattern Watershed of project area 2. Drainages outlets and their Impacts. 3. Role of Geometric/Pavement designer and construction engineer 4. Drainage Outlets vs community 5. Conclusions

Watershed in Global Perspective

Country’s Dendritic Pattern

Watershed of Project a Area Khundrungay Homa Khola Sunkosh river

Drain Outlets vs Road 6 4 5 Drainage system includes: • Catchment area Soil conditions Road geometry Cross falls Pavement designs Drainage outlets Cross drainage spacing Open drains Under ground drains • Soil types • • • 2 Impacts: ü Erosions due to outlet discharge 3 • • • Planning, Designing & Construction phases 1

IMPACTS u/s culvert choked & submerged by debris Choked culvert Formation of new drain by runoff Gabion cascade

IMPACTS Road bend failure Road edge scoring Road edge failure R/wall Toe Failure

Role of geometric/Pavement designer & construction engineer GEOLOGICAL MAP OF BHUTAN

Role of geometric/Pavement designer & construction engineer Source of water in Roads

Role of geometric/Pavement designer & construction engineer Understanding of water movements

Role of Geometric/Pavement designer & construction engineer Roadway & Roadside Drainage

Role of Geometric/Pavement designer & construction engineer Choice of Appropriate structures

DRAINAGE OUTLETS VS COMMUNITY Deorali Village Impacts: • • • Damage to public properties No outlet space Alteration of dr. AIN DESIGN

CONCLUSIONS 1. Review of Road design guide lines is suggested incorporating following items: Designing and planning of drainage system ü Design of erosion and sedimentation control. ü Good management Practices (GMP) in drainage constructions. ü Present practice of roadside drains may be reviewed further. ü

CONCLUSIONS 2. An adequate time to be allocated for planning and design phases. 3. A thorough review is needed by a group of expertise for any designs submitted by consultancy firms before acceptance 4. Drainage outlet rights to be incorporated in road Act. 5. In-house capacity building by road specialists and principal engineers to fresh and young engineers.

FUNS ON ROAD TERMINOLOGY 1. Permanent works (PW) 2. Box cutting 1. Permanent works (PW) = “Long term Structures” 2. Box cutting = “Through cutting or in cutting”

THANK YOU FOR YOUR KIND ATTENTION