DEWAL DRAIN NETWORK

CONDITION SURVEY

DEWAL DRAIN NETWORK

The existing intercept drain is unable to accomplish the purpose it was actually made for i.e. to entrap the major part of surface runoff to avoid percolation, which can catalyze the landslide hazard. The breakage and choking caused the drain to be ineffective. Primary reasons for the deterioration of drain are ingress of water through the interface of elevated upslope and natural slope and incompetent quality of material used for the construction of drain. On the whole the drains require proper construction i.e. upslope drain wall should flush with the existing slope, cleaning, filling of cracks and masonry repair at various parts of the drain network. Pictures of worn out parts of drain and their location plan are attached along. Other required repairs and rehabilitations are given in the Table as follows;

DEWAL DRAIN NETWORK

Sr. #

Chainage * Photograph #

Remarks/Observations

1. 0+005 O1 The slopes of the copping are not compatible with the uphill slope and hence not favorable to catch the flow of rain water.

2. 0+013 02 Open cracks are present on both walls and reduce the efficiency of drain.

3. 0+030 03 Upslope wall of existing cascade drain at this chainage require masonry repair and to make this wall compatible with the existing slope to entrap the rain water

4. 0+040 04 & 05 Catchment pit should be provided at the interception of new and old drains just before the point from where the old drain eroded.

5. 0+048 06 & 07 Upslope wall is higher than the existing slope, make the drain inefficient. The slopes of the copping are not compatible with the uphill slope and hence not favorable to catch the flow of rain water.

6. 0+067 08 Open cracks are present in walls This is a common observation of ingress of water and has observed at various chainages.

7. 0+080 09 & 10 Masonry repair is required as copping is broken and open cracks are present.

8. 11 Open cracks in downslope wall of drain near the house at hilltop need repairing.

9. 0+090 12 & 13 Worn out copping and cracks in walls. Masonry repair is required.

10. 0+104 14 & 15 Masonry repair required. Worn out copping and walls.

11. 0+114 16 The downslope wall at the edge of a turn at this chainage is completely damaged and so as the upslope wall at the corner of the turn. Masonry repair is required .

DEWAL DRAIN NETWORK

Sr. # Chainage*

Photograph #

Remarks/Observations

12. 0+120 17 Walls are cracked and broken, drain is choked due to vegetation. Cleaning is required to mitigate the choking.

13. 0+127 18 & 19 Open cracks are present same as depicted in FIG 8,11 and 17. repairing is required.

14. 0+138 20 & 21 Cleaning of drain and repairing of open cracks is required to avoid percolation

15. 0+160 22 & 23 Upslope wall is higher than existing slope.

16. 0+172 24 & 25 Walls are broken. Masonry repair is required.

17. 0+178 26 & 26B Masonry repair is required the upslope wall is eroded due to ingress of water

18. 0+208 27,28 & 28B Walls are broken and the drain is completely choked with detached material from walls.

19. 0+219 29 The drain left incomplete about 15 feet before approaching the road.

20. 0+264 30 The existing Culvert on road is completely choked.

*Chainage: starting from Murree end to locate and identify the nature of problem as depicted in table above.

DEWAL DRAIN NETWORK

Plate 01 (Ch. 0+005) Slopes of the copping

are not compatible with the uphill slope

and hence not favorable to catch the

flow of rain water.

Plate 02 (Ch. 0+013) Open cracks are present and reduce the efficiency of drain. Repairing is

required

Upslope Wall

Downslope Wall

Open Crack in Upslope Wall

DEWAL DRAIN NETWORK

Plate 03 (Ch. 0+030) Upslope wall of existing cascade drain at this chainage require masonry repair

Upslope Wall

DEWAL DRAIN NETWORK

Plate 05 (Ch. 0+048 ) Catchment pit should be provided at the interception of new and old drains just before the point from where the old drain eroded.

Downslope Wall

Where the existing drain eroded

Upslope Wall

Downslope Wall

Newly constructed Drain

Plate 04(Ch. 0+040) Catchment pit is required at the junction of newly

constructed drain an existing drain at chainage 0+040

DEWAL DRAIN NETWORK

Plate 07 (Ch. 0+048 ) Upslope wall is higher and

the slopes of copping are in opposite direction to the

existing natural slope

Upslope wall

Plate 06(Ch. 0+067) Upslope wall is higher and the slopes of

copping are in opposite direction to the existing natural slope

Upslope wall

Upslope wall

Erosion of Upslope wall

Plate 08 (Ch. 0+067) Typical observation of ingress of water causing erosion/damage of

upslope stone wall

DEWAL DRAIN NETWORK

Plate 09 (Ch.0+080) Masonry repair is required as copping is broken

and open cracks are present.

Plate 10 (Ch. 0+080 ) Masonry repair is required as the

downslope wall eroded/damaged

Cracks in Downslope Wall

Downslope wall eroded

DEWAL DRAIN NETWORK

Plate 11 (Ch. ) Open cracks in downslope wall of drain near the house at hilltop need repairing.

Downslope Wall

DEWAL DRAIN NETWORK

Plate 13 (Ch. 0+090 ) Masonry repair is required as there are

open cracks in walls

Downslope WallDownslope Wall eroded/damaged

Plate 12 (Ch. 0+090 ) Masonry repair is required for the broken

copping of downslope wall.

DEWAL DRAIN NETWORK

Plate 15(Ch. 0+104 ) Masonry repair is required. The slope of the wall has

eroded.

Downslope wall

Downslope wall

Plate 14 (Ch. 0+104 ) Masonry repair is required. The slope of

the wall has eroded.

Plate 16 (Ch. 0+114 ) The downslope wall at the edge of a turn at this chainage is

completely damaged and so as the upslope wall at the corner of the turn. Masonry repair is

required .

Downslope wall is damaged

Downslope Wall

Upslope wall

Plate 17 (Ch. 0+120) Cleaning of drain and

masonry repair of broken walls

DEWAL DRAIN NETWORK

Plate 18 (Ch. 0+127) Open cracks are present same as depicted in Plate # 8 and 11 repairing is required.

Downslope wallUpslope wall

Plate 19 (Ch. 0+127) Open cracks are present same as depicted in

Plate # 8,11 and 18. repairing is required.

Upslope wall

DEWAL DRAIN NETWORK

Plate 21 (Ch. 0+138) Open cracks are present. Drain is choked due to vegetation.

Upslope wall

Upslope wallDownslop

e Wall

Plate 20(Ch. 0+138) Cleaning of drain and

repairing of open cracks is required to avoid percolation

DEWAL DRAIN NETWORK

Plate 22 (Ch. 0+160) Upslope wall is higher than existing slope same as depicted in Plate# 06

and 07. Plate 23(Ch. 0+160) Upslope wall is higher than existing slope

Upslope wall

Downslope wall

DEWAL DRAIN NETWORK

Plate 24(Ch. 0+172) Masonry repair is required the downslope

wall is eroded/damaged.

Plate 25(Ch. 0+172) Another view of

Plate # 24.

Downslope wall

Downslope wall

DEWAL DRAIN NETWORK

Plate 26(Ch. 0+178) Masonry repair is required the upslope wall is eroded due to

ingress of waterPlate 26B(Ch. 0+178 ) Open

cracks are present on the upslope wall and need repairing

Upslope wall

Upslope wall

DEWAL DRAIN NETWORK

Plate 27(Ch. 0+208) Walls are broken and the drain is completely

choked with detached material from walls. Cleaning of choked drain

is required

Plate 28(Ch. 0+208) Masonry repair and cleaning is required

Upslope wall

Upslope wall

DEWAL DRAIN NETWORK

Plate 28B(Ch. 0+208) another view of Plate# 28

Plate 29(Ch. 0+219) A step should be constructed to approach

the road

Upslope wallUpslope wall

DEWAL DRAIN NETWORK

Plate 30(Ch. 0+264) Cleaning of Culvert is required.

Existing culvert

Choked

DEWAL DRAIN NETWORK

Rain water action played an important role in the disintegration of drains in terms of cracks and erosion of masonry material.

The cracked and damaged walls of drains (as shown in Plate # 9,8,11,19,20,21,24,25 and 26B) reduce the capability to entrap the surface runoff as the water would pecolate through these cracks.

The damaged copping of drains (as shown in Plate # 3,5,10,12) also make the drains inefficient as over topping of the flowing water (coming from upslope towards drain) would take place.

The slopes of copping of walls (as shown in Plate # 1,6 and 7) are not favorable to entrap the flowing water as they slope in the opposite direction to the existing natural slope and would reverse the water flowing towards the drain. The upslope walls of the drains at these chainages are also higher than the existing natural slope which is another hindrance for the runoff to be entrapped properly

Choking of drain due to vegetation and detached mass from erosion of existing Culvert (as shown in Plate # 17,21,27,28 and 30) severely abandon the drain and make it inefficient as the water entrapped in drain would not pass through and exit properly rather it would accumulate in the drain and percolate through weaker zones and interstices to an undesired destination.

The drain is incomplete at the end (as shown in Plate # 29). About 15 to 20 feet before the drain approaches the road, it has not been constructed and left incomplete which can spread around the entrapped flowing water before heading towards the culvert to be egressed.