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CHAPTER - V

PRESENT STATUS OF THE WATER CONSERVATION

STRUCTURES AND THEIR UTILITY.

For recharging the ground water table in watershed areas, large number of

water conservation structures such as Percolation Tanks, Check dams, K. T.

Weirs and Earthen Bunds have been constructed across the main nala and their

tributaries. [Table No. 33]

In the past there was a practice to construct Percolation Tanks and K. T.

Weirs beyond the foothill regions where nala becomes broad. However,

subsequently as a part of watershed development programmes, concrete or

masonry check dams of different sizes and Earthen Bunds were also constructed

at the higher reaches to get the benefit of percolated water for low lying areas and

to check the velocity of water thereby avoiding the soil erosion.

It seems that many of the water conservation structures might not have

been constructed meticulously by adapting civil engineering norms and observing

strict quality controls. It was observed that after the construction, these structures

were left uncared for and were deprived of proper maintenance. All such state of

affairs and measures in case of their repairs and modifications whatsoever have

been dealt within the present chapter.

Table No. 33 : Water Conservation Structures Constructed in Watershed Areas Studied

Sr. No.

Name of the Watershed

No. of K. T.

Weirs

No. of Earthen Bunds

No. of Masonry

Check Dams

No. of M.I. Tank/ P.T.

1 Nashera 03 ---- ---- 01 Abandoned 2 Ashewadi 09 04 --- ---- 3 M. Phule 06 --- --- ---- 4 Jai Yogeshwar 11 --- ---- ---- 5 Panoli --- --- 02 03 6 Hivre Bazar 04 07 02 02 7 Hivre Korda --- 09 ---- -- 8 Kachhe Ghati --- 04 05 --- 9 Kadwanchi 01 --- 03 ---

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The present status of the water conservation structures and the

suggestions for their repairs and modifications are described below serially.

1) Watershed Area at Nashera

Three K.T. Weirs are constructed across Deobandh tributary to store water

of late rains. Generally gates of the K.T. Weir are installed in the second week of

September and are removed before the onset of the next monsoon to let

floodwater pass over. But it seems that this practice is not followed since the time

of construction of these K. T. weirs.

Three such K. T. Weirs were constructed at following locations. [Table No. 34]

Table No. 34 : Details of Water Conservation Structures across Deobandh Tributary

Name of the Structure Length in m. Height in m. Top width in m.

K. T. Weir No. 1 21.15 1.90 1.6

K. T. Weir No. 2 25.63 1.25 2.75

K. T. Weir No. 3 29 2.5 1

K.T. Weir No.1 [Fig. No. 157]

At Ch.619.5 m. K.T. Weir was constructed in 1997-98 [Fig. No. 157] having

following dimensions.

Length: 21.15 m. Height: 1.90 m. Top width: 1.6 m.

Two gates are provided to in the weir. The wall of the middle block of the

K.T. Weir has collapsed above the ground level due to washing away of masonry

blocks. As per the information given by the local people, although gates were

brought at the site alright to close the outlets of the K.T. Weir, they could not be

fitted in the K.T. Weir as the distance between the two channels of the outlet is

shorter than the width of the gates. Therefore gates were kept lying in abeyance

on the banks of Deobandh tributary below the highest flood level. During the

floods these gates were washed away and are now lying on the bed of Deobandh

tributary and are totally in rusted condition.

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Suggestions:

It is suggested that new gates, with appropriate width may be fitted in the

K.T. Weir to effect storage of water. Similarly the portion of the dyke occurring

below the left abutment may be concreted and repairs of the fallen away portion at

the left abutment may be undertaken.

If this K.T. Weir is properly repaired the stored water in K.T. Weir may

percolate laterally through Dyke Nos. N-5 & N-6, which cut across the

submergence portion of K.T. Weir, and adjacent areas, may be benefited.

K.T. Weir No. 2 [Fig. No. 158]

It is constructed at Ch.1221.8 m. in 1997-98. Its dimensions are

Length: 25.63 m. Height: 1.25 m. Top width: 2.75 m.

Two gates are provided to it. [Fig.No.158] It was observed that in one

outlet, erosion of the concrete pavements provided at the sill and masonry work

made for the foundation are washed away creating voids. Through these voids

large percolation of stored water takes place and K.T. Weir becomes empty

immediately after the rainy season. According to the local people the gates are

installed permanently.

Suggestions:

It is suggested that repairs of the foundation work may be undertaken to

avoid percolation of water. Similarly, maintenance and installation of the new

gates may be entrusted to the authorities of the Grampanchayat.


This K.T. Weir was constructed at ch.1429.65 m in the year 1997. having

dimensions

Length: 29 m. Height: 2.5 m. Top width: 1 m.

Two gates have been provided in this K.T. Weir. According to the

information given by the local people, the gates of this weir cannot be removed as

they have got stuck up tightly [Fig. No. 159] in the channels. Therefore, in rainy

season floods pass over the crest of the K.T. Weir. It was also told that heavy

leakage develops along the junction between the gates and the piers. Water also

percolates through the masonry work constructed at the foundation.

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It was also observed that K.T. Weir has almost got silted up and Deobandh

tributary is filled up with silt and the mud upto crest of the K. T. Weir.

Suggestions:

It is suggested that desilting of the K. T. Weir and repairs of the foundation

work and the work of new packers at the gates may be undertaken immediately.

2) Ashewadi Watershed Area

The necessity of modifications and repairs of water conservation

structures constructed in the campus of proposed Medical College at

Ashewadi, district Nashik are given below.

In the watershed area of Ashewadi, 9 K. T. weirs and 4 earthen bunds

have been constructed to store run off of the area [Table No. 33 and 35- A

and B]

Table No. 35 - A : Details Showing Water Conservation Structures in Ashewadi Area

Name of the structure and stream No.

Length in m.

Height in m.

No. of Outlets

K T W No. – 1 ( S-1) 44.05 3.50 TWO Height 2.8 m., Width 1 m.

K T W No. –2 (S-2) 30.60 3.80 ONE Height 0.5 m. Top Width 6 m.

Height 3.1 m. Bottom Width 1 m.

K T W No. –3 (S-2) 47.84 1.64 TWO Height 0.94 m. Bottom Width 1 m.

K T W. No. – 4 (S-3) 26.20 3.55 ONE Height 0.5 m. Top Width 7.6 m

Height 3.3 m. Bottom Width 1m.

K T W. No– 5 (S-4) 25.00 3.40 ONE Top Width 6 m. Height 3.1 m

Bottom Width 1m.

K T W. No.– 6 (S-4) 75 6.00 TWO Height 4.80 m. Width 1m

K T W. No.– 7 (S-5) 30.14 3.55 ONE Height 2.75 m.

Width Top 6.18 m. and Bottom 1.0 m.

K T W. No. –8 ( S-6 ) 25.40 4.10 ONE Height 3.8 m.

Width Top 6.4 m. and Bottom 1 m.

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Table No. 35 - B : Details Showing Earthen Bunds in Ashewadi Area

Number Length in m. Height in m. No. of Outlets

**E.B.– 1 (S -1) 26.0 2.0 ----------

E. B. – 2 (S -2) 50.8 2.20 ----------

E.B. – 3(S -5) 35.5 2.35 ----------

E. B. -4 (S -6) 26.5 2.40 ----------

* Kolhapur Type of Weir; ** Earthen Bunds

The present status of these structures and suggestions for their

modifications and repairs are given below serially.


It has been constructed across Stream Number 1 (S-1) at the

southern boundary wall of the area. Its dimensions are [Fig. No. 160 ]

Length: 44.05 m. Height: 3.50 m.

Outlets: 2 (Height 2.80 m; Width 1 m of each outlet)

Towards downstream of K.T. Weir No. 1, at a distance of about 6.75

m, a waterfall having height 1.5 m is developed. [ Fig. No.161] During the

rainy season forceful floodwater would pass through the outlets. Due to the

force of the water, erosion of the face of the waterfall would occur and

gradually waterfall would migrate towards K.T. Weir No. 1. It is likely that in

due course of time the waterfall may migrate up to the toe of K.T. Weir No. 1

and may scour its foundation.

Suggestions:

1) As K.T. Weir No.1 is constructed at the southern border of the area,

the region, beyond the campus of the Medical College may get benefit of

percolation of water. To avoid loss of water by percolation from K.T. Weir

No. 1, it is suggested that a blanket of impervious soil may be spread in

reservoir area touching the u/s face of K.T. weir No. 1. So that, this K.T.

Weir would act as storage tank and water would be available during summer

season.

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2) It is also suggested that, the weathered Amygdaloidal Basalt, which

is exposed towards downstream and at the base of the K. T. Weir, may be

covered by concrete giving Ogee Shape.

K.T. Weir No. 2

It has been constructed across Stream No. 2 (S-2). with following

dimensions

Length: 30.6 m.; Top Width : 0.60 m

Channel Width: 1 m; Height of the channel: 3.1 m

Outlets: 1, Upper outlet width: 0.6 m

Lower outlet width: 1.0 m; Height: 3.1 m

Immediately towards downstream of this structure loose material has been

dumped to avoid erosion of bed rock by impact of water. [Fig. No. 162] But during

the floods in rainy season this dumped material would get washed away and

would be deposited in the submergence area of Earthen Bund No.2 which is

constructed towards downstream at a distance of about 80.5 m

Suggestions:

1) It is suggested that the dumped material should be removed and concrete

apron should be provided on the bed of the Stream No. 2 up to a distance of 15

m. from the toe of K.T. Weir No.2.

2) It is also observed that the length of the weir is rather insufficient as

compared to the height of the water column, which would spread beyond both the

abutments. Due to which outflanking from the end portion of the K.T. Weir would

occur resulting in the erosion of the abutment portion.

3) Therefore, it is suggested that wing walls may be provided towards

upstream of K.T. Weir No. 2 to avoid outflanking and erosion of abutment portion.

[Fig. No. 163]

K.T. Weir No.3

This K.T. Weir has been constructed across Stream No.2 (S - 2) along the

southern boundary of the area and towards downstream of Earthen Bund No. 2.

Its dimensions are

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Length - 47.84 m. Height - 1.64 m.

Outlets - Two (Height. = 0.94 m, Width = 1.0 m )

Suggestions:

1) In the reservoir area of this K.T. Weir, heap of loose rock and soil has

been dumped over a large area [Fig. No. 164] due to which storage capacity of

this K.T. Weir is reduced. Therefore it is suggested that the dumped material

should be removed.

2) Immediately towards downstream of the outlet, sheet jointed weathered

erodable Amygdaloidal Basalt is exposed up to a distance of 16 m. During rainy

season due to impact of the floodwater, erosion of weathered material may occur.

Therefore it is suggested that the weathered rock exposed towards downstream

of K.T. Weir may be covered by providing pitching of loose rock boulders so as to

avoid erosion of weathered Amygdaloidal Basalt.

3) The same weathered sheet jointed Amygdaloidal Basalt is also exposed

in the reservoir area. Therefore it is suggested that the weathered Amygdaloidal

Basalt, which is exposed towards u/s, may be covered by impervious soil.

K.T. Weir No.4

This K.T. Weir has been constructed across Stream No.3 (S - 3). It is

located at a distance of about 96 m towards u/s of the lower ring road having

dimensions

Length - 26.20 m : Height - 3.55 m

Outlets - Top Width = 7.6 m: Height = 0.5 m (Top Outlet)

Bottom width = 1 m (Bottom Outlet)

Fresh Amygdaloidal Basalt is exposed towards both upstream and

downstream of this structure. Towards downstream, gradient of the stream is

rather steep. A small waterfall has developed towards downstream at distance of

19.5 m. [Fig. No. 165]

The ends of this K. T. weir are abruptly terminated without anchoring in the

abutment rock. [Fig. No. 166] Therefore, to avoid outflanking of water during

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torrential rains, towards u/s beyond both the ends of the structure loose mud is

stacked. [Fig. No. 166]

Suggestions:

1) It is suggested that in place of the mud which is stacked beyond both

end of the structure masonry wing wall may be provided.

2) It is also suggested that weathered Amygdaloidal Basalt which is

exposed towards downstream and on the face of the waterfall may be

covered by concrete giving Ogee Shape.

K.T. Weir No. 5

It is constructed across Stream No.4 (S-4) at a distance of 90 m from

Ring Road towards northern boundary. Its dimensions are

Length -25 m; Height - 3.4 m

Outlet – 01 (Ht =3.1m. Width of upper outlet 6 m.

Width of Lower outlet 1m.Height - 3.9)

Towards downstream of the structure, fresh Amygdaloidal Basalt is

exposed. Towards upstream beyond both the ends of the structure loose

mud is stacked to avoid outflanking of water during torrential rains.

Suggestions:

It is suggested that in place of the mud, which is stacked beyond both

end of the structure masonry wing wall, may be provided.


This structure has been constructed across Stream No.4 (S-4)

Its dimensions are

Length - 75 m. Height - 6m. Outlet - 2 (ht-4.80 m. width 1 m. of each

outlet)

Towards downstream of the structure a short waterfall has developed. [Fig.

No. 167]

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Towards upstream beyond both the ends of the structure loose mud

is stacked to avoid outflanking of water during torrential rains by washing

away of pile of mud.

Suggestions:

1) It is suggested that in place of the mud, which is stacked beyond both

end of the structure masonry wing wall, may be provided.

2) It is also suggested that weathered Amygdaloidal Basalt, which is

exposed towards downstream and on the face of the waterfall, may be

covered by concrete giving ogee shape.

K.T. Weir No. 7

This structure has been constructed across Stream No.5. Its

dimensions are

Length - 30.14 m. Height - 3.55 m. Outlet - 01(width of upper outlet 6

m, Width of bottom outlet 1.m Height of outlet=2.75 m)

The valley of Stream No.5 is quite broad and deep. As compared to

the depth of the valley, the height of the structure constructed is short.

Therefore, though valley has got quite large capacity to store water. The

height of the structure is inadequate.

Immediately towards d/s, a small waterfall is developed in sheet

jointed, weathered Amygdaloidal Basalt. [ Fig. No.168]

Suggestions

1) It is suggested that the height of the existing structure may be

increased to store maximum quantity of water.

2) The face of the waterfall occurring towards downstream may be lined

by masonry or concrete to avoid its migration towards K. T. Weir.

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K.T. Weir No. 8

This structure has been constructed across Stream No.6 (S-6) in the

upstream side of stream, valley is quite deep in which Amygdaloidal Basalt is

exposed.

Its dimensions are

Length=25.40 m. Height=4.1 m. Outlet=01 (width of upstream outlet

6.4 m, Height of upstream outlet 0.5 m, Width of bottom 1.0m, Height of

bottom 3.7 m)

As compared to the depth of the valley, the height of the structure

constructed is short. Therefore, though valley has got quite large capacity to

store water, the height of the structure is inadequate [Fig. No. 169].

Suggestions:

It is suggested that the height of the existing structure may be

increased to store maximum quantity of water. If the height is not to be

raised beyond the ends of the structure wing walls may be constructed to

avoid out flanking. Immediately towards downstream of the structure, fresh

Amygdaloidal Basalt is exposed therefore there would not be erosion of tail

Channel.

K.T. Weir No. 9

This structure has been constructed across Stream No. (S - 6). Along

southern boundary of the area. [Fig. No.169] Its dimensions are

Length=63.24 m. ; Height: 4.1m

Outlet=02 Height 1 m of each outlet

Towards both downstream and upstream, weathered [Fig. No. 169]

Sheet jointed Amygdaloidal Basalt is exposed through which the stored

water from the stream may percolate beyond the campus of the area.

Towards downstream cultivated land is occurring closed to the right

bank of the stream. During high floods it is likely that cultivated land may get

washed away.

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Suggestions:

It is suggested that a guide wall or pitching of rock up to considerable

height and distance may be constructed along the right bank of the stream to

channelize flow of water.

EARTHEN BUNDS

Earthen Bund No.1 ( E.B. No.1)

This bund has been constructed across Stream No. 1 (S-1). As valley

is shallow and no other water conservation structure has been constructed

towards upstream of the Bund No. 1 (S-1), water is collected at Earthen

Bund-1. [Fig. No. 170]

The dimensions of this Earthen Bund are

Length: 26.0 m. : Height: 2.0 m.

As the bund is constructed by only dumping loose soil without

providing zones and compaction of mud. Therefore, it is likely that voids may

be developed and loss of water may occur.

It is likely that outflanking may occur from the end portion of the

earthen bund.

Suggestions:

(i) It is suggested that the existing dumped mud may be properly

compacted.

(ii) To raise the height of the earthen bund, base width may be increased

proportionately.

(iii) It is suggested that pitching may be provided on upstream and

downstream face of the earthen bund.

Earthen Bund No.2 (E. B. No. 2)

It s constructed across Stream No.2 towards downstream of K.T. Weir

No .2. having dimensions

Length: 50.8 m. Height: 2.2 m

As the bund is constructed by only dumping loose soil without

providing zones and compaction of mud. [Fig. No. 171] Therefore, it is likely

that voids may be developed and loss of water may occur.

117

During rainy season, if the gates were not fitted in K.T. Weir No.2,

floodwater would accumulate in Earthen Bund No.2. The capacity of Earthen

Bund No.2 would not be sufficient to hold additional floodwater and in that case

water would overflow the crest of Earthen Bund No.2 and major portion of this

bund may be washed away.

Suggestions:

1) It is suggested that the existing dumped mud may be properly

compacted.

2) To raise the height of the earthen bund, base width may be increased

proportionately.

3) It is also suggested that pitching may be provided on upstream and

downstream face of the earthen bund.

4) For the sake of safety of this bund gates in K.T. Weir No.2 may be fitted

permanently and if required only regulated flood may be released by lifting

of the gates.

Earthen Bund No.3 ( E. B. No.3)

This has been constructed across Stream No.5 (S-5), towards downstream

of K.T. Weir No. 7 at the distance of 54 m.

Its dimensions are

Length: 35.5m. Height: 2.35 m.


concentrated flood would get accumulated in Earthen Bund No.3. The capacity of

Earthen Bund No.3 would not be sufficient to store entire flood and in that case

water would pass over the crest of Earthen Bund No.3 and major portion of this

bund may be washed away.

Suggestion:

For the sake of safety of this bund, gates in K.T. Weir No.7 may be fitted

permanently and if required only regulated flood may be released by lifting of the

gates.

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Earthen Bund No. 4 (E. B. No.4)

This structure has been constructed across Stream No.6 (S-6) towards

downstream of K.T. Weir No. 8 at the distance of 44.2 m.

It was observed that quite heterogeneous, and small sized pieces of rocks

along with some soil are used in the construction. Due to which, the structure has

become weak and permeable.


concentrated flood would get accumulated in Earthen Bund No.4. The capacity of

Earthen Bund No.4 would not be sufficient to store entire flood and in that case

water would pass over the crest of Earthen Bund No.4 and major portion of this

bund may be washed away. Therefore, it is likely that water may percolate

through the body of this bund.

Suggestions:

For the sake of safety of this bund gates in K.T. Weir No.8 may be fitted

permanently and if required only regulated flood may be released by lifting of the

gates.

3) Mahatma Phule Society, Ozar, Dist .Nashik

As given in Table No. 5 six K.T. Weirs are constructed across Satwai Nala.

These K.T. weirs were constructed much before the diversion of canal water into

Satwai Nala. Therefore, these K.T. Weirs used to store floods of only late rains.

But subsequently when canal water was diverted, through Satwai Nala and to

store water outlets of these structures were permanently closed either by steel

gates or by constructing concrete diaphragms. After closing the gates, these K.T.

Weirs were started acting as storage tanks to store diverted water of the canal.

But no modifications in their structures were made like providing ogee shaped

downstream face of the gate and the bucket in front of it. The modifications

required are given in detail at the end of description of the structure.

During every rotation when K.T. Weirs become full of water, water

overflows from the crest of the K.T. Weir like a waterfall.

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Condition of K.T. Weirs

K.T. Weir No. 1

It is located at Ch.140 m Dimensions are as follows

Length: 35. 5 m. Height: 2.5 m

Top width: 1 m. Outlet 3 (Height: 2.5m, Width: 2 m)

The outlets of this Weir are closed by concrete diaphragm. As stored water

overflows from the crest, it makes impact at the toe of the Weir causing erosion of

rock at the toe. This Weir is almost silted up. Only 1.5 m column of water stands

in the Weir [Fig. No. 49] reducing major storage capacity of the Weir. As per the

information given by Patkari after every rotation, water remains in the weir for 15

days, which indicates that percolation might have stopped through the rock

occurring along the banks of the nala due to silting.

K.T. Weir No. 2

It is located at Ch.550 m. Its dimensions are as follows

Length: 14 m. Top width: 0.65 m.

Height: 1.3 m. Outlets: 2 (Height - 0.08 m., Width- 0.9 m.)

The outlets of this Weir are closed by concrete diaphragm. As stored water

overflows from the crest, it makes impact at the toe causing erosion of the rock at

the toe. This weir is almost silted up and only short column of water is created.

[Fig. No. 50] As per the information given by Patkari, this Weir becomes empty

due to leakage developed between the bottom of the Weir and foundation of the

rock. In the toe region, gap is formed between the foundation rock and K.T. Weir,

which is clearly seen.

K.T. Weir No. 3

It is located at Ch. 847 m. Its dimensions are as follows

Length: 10.5 m. Height: 1 m.

Top width: 0.6 m. Outlets 2 Nos. (Height: 0.7 m; Width: 0.9 m.)

By constructing concrete diaphragm, outlets of this weir are permanently

closed towards downstream, jointed Compact Basalt is exposed. As water flows

120

from the top of the Weir towards downstream a narrow gully is formed in the bed

of the nala due to erosion.

As this Weir is almost silted up it never becomes empty and backwater

spreads up to Ch.1050 m. [Fig. No.172] Therefore, this Weir stores small quantity

of water released during every rotation.

K.T. Weir No. 4

It is located at Ch.1270 m.

Length: 19 m. Height: 1.2 m

Top width: 1 m. Outlets: 2 Nos. (Height: 0.9 m; Width: 1m)

The outlets of the Weir are permanently closed by concrete diaphragm.

The foundation of this Weir is taken on closely jointed Compact Basalt in which

spheroidal weathering is developed. These conditions are very much favourable

for percolation of water. However, a permanent standing pool of water remains in

the Weir. It is due to total silting up of the bed of the nala. Due to silting an

impervious blanket is formed on permeable strata. Therefore percolation is not

taking place [Fig. No. 52]

K.T. Weir No. 5


Length: 16 m. Height: 0.9 m.

Top width: 0.9 m. Outlets: 1 No. (Height: 0.9 m; Width: 0.9 m.)

Unlike K.T. Weir Nos. 1 to 4, gates are not permanently closed but they are

temporarily sealed by loose pieces of rock.

Just downstream of the gate, a narrow gully is formed due to erosion of the

rock. At the toe, mortar is removed and gap is formed between the body of the

Weir and the foundation rock.

As length of this Weir is insufficient and proper keying has not been made

in country rock, outflanking has taken place near the right abutment.

At the site of the Weir valley is almost flat therefore site is not suitable for

construction of Weir.

121

Though silting has taken place towards upstream of Weir, along the banks,

closely spaced jointed Compact Basalt is occurring, through which water

percolates laterally.

K.T. Weir No. 6


Length: 6.7 m. Height: 1.4 m

Top width: 0.9 m. Outlets: 2 (Height: 1.4 m.; Width: 2 m.)

"Niphad Co-operative Sugar Factory" constructed this Weir during the

financial year 1998-99 i.e. in the last phase of developmental activity.

It is suggested that the gates of the Weir may be removed at the beginning

of every rotation they may be closed subsequently, after filling of the K.T. Weir

No. 5, so that water will be stored in K.T. Weir No. 6 and minimum erosion at the

toe will take place if at all water overflows from the crest of this Weir.

On the basis of observations carried out of these structures

recommendations are suggested in the later part of this chapter.

Conditions of Minors and Diversion Channels:

A) Conditions of Minors:

It is observed that minors, after entering into the area of Mahatma Phule

Society, are in bad state of preservation. The erosion has taken place along

Minor No. 18 and at a number of places masonry lining has collapsed through

which leakage of water takes place in the area where no cultivation is undertaken.

[Fig.No.173] Due to loss of water through damaged portion of the minors effective

supply of water to the downstream farms is affected.

B) Condition of Diversion Channels:

Diversion channels are provided to divert water from Minor Nos. 17 and 18

to Satwai Nala. These diversion channels are in the form of unlined shallow

trenches through which water may be percolating giving benefit to the cultivated

area.

122

Repairs and Modifications of the Existing Structures

On Satwai Nala all Weirs are constructed as per the typical design of

Kolhapur Type of weirs. Kolhapur Type of weir is constructed to store water of the

late rains, which is received after mid September. Therefore gates are fitted after

15th October and gates are removed before the commencement of next rainy

season to pass the floods. It means the design of K.T. Weirs is not meant for

creating permanent storage of water. But in the area studied these Weirs are

being used for making permanent storages. As the outlets of the Weirs are

permanently closed either by fitting the steel gates or by providing concrete

diaphragm.

Therefore, after every rotation water fills up these structures and overflows

from the crest. As no energy dissipation arrangements have been made, water

from the crest of the weir falls towards downstream in the form of a waterfall

making concentrated impact in the region of the toe. It is observed that damage

has caused in the toe portion by forming gaps between the foundation rock and

the base of the K.T. Weirs As per the information given by Patkari, profuse

leakage takes place from the channels of the gates of the Weirs and also from the

foundation rock. If such percolation occurs continuously then the bond between

the masonry wall and the foundation rock would be weakened and in that case

structure may collapse.

Therefore, it is recommended that on priority basis proper modification in

existing structures be made as described in later part of this Chapter.

4) Jai Yogeshwar Society, Ozar, Dist. Nashik

Even though assured water supply was made available through Waghad

canal to Jai Yogeshwar Society. The society always experienced scarcity of water

for irrigation.

As the society lies in the tail end portion of the Waghad canal, sufficient

quantity of water never reaches up to the area of the society. Therefore, even

though all arrangement was made for distribution to provide canal water in the

entire area, water never reaches to the entire region of the society.

123

Therefore, it was decided to store rainwater in Ghagre nala by constructing

K .T. Weirs. Accordingly, 11 K.T. Weirs were constructed across it. [Table No. 8]

After the construction of these structures, for the first few years society got

benefit of percolated water. But gradually, percolation of water was dwindled and

at present it seems the structures have become defunct. It is mainly due to large

silt that has deposited in the submergence area of these structures and also due

to large percolation of water from the structures through voids, which are formed

in the foundation.

To get the full benefit of these structures the repairs and maintenance

should be taken immediately on war footing as given below.

K.T. Weir No.1

Length - 21.2 m. Top Width - 0.58 m. Height - 1.68 m.

It is constructed by using random rubble masonry. Two outlets are provided

in this K.T. Weir. But at the time of visit, the outlets are found to be open. It was

observed that thick blanket of silt is deposited in the submergence area of this

K.T. Weir.

K.T. Weir No.2 [Fig. No. 174 ]

Length - 8 m. Top Width - 1.96 m. Height - 1.06 m

Two outlets are provided to this K.T. Weir but they are permanently closed

by constructing concrete diaphragm. As in the region of this K.T. Weir, sheet

jointed amygdaloidal basalt is occurring and scouring of rock has developed close

to the toe portion of the weir. [Fig. No. 174]

It was also observed the pointing of the masonry structure is removed and

small voids are developed in the body of the weir by washing away of mortar used

in the construction.

As per the information given by the local people water from this K.T. Weir,

percolates through the body of the structure.

124

Suggestions:

It is suggested that as given in later part of this Chapter, a concrete apron,

covering the toe of the structure up to some distance may be provided to avoid

scouring and undermining of the toe portion.

Due to continuous percolation of water from the body of the structure,

masonry blocks would become loose and gradually they would be washed away.

K.T. Weir No.3

Length - 11.1 m. Top Width - 0.7 m. Height - 0.93 m

Two outlets are provided in this K.T. weir but they are permanently closed.

Similar to the K.T. Weir No.2 scouring has occurred close to the toe portion. Due

to which masonry used in the foundation is exposed. [Fig. No. 175]

Suggestions:

It is suggested that as given earlier, a concrete apron covering the toe of

the structure up to some distance may be provided to avoid scouring and

undermining of the toe portion.

Due to continuous percolation of water from the body of the structure,

masonry would become loose and gradually it would get washed away.

K.T. Weir

Length -11.8 m. Top Width - 0.6 m. Height - 0.8 m.

Two outlets have been provided to this structure. In the submergence area

silting has taken place.

It was observed that masonry from the wall has dislodged and totally

removed at places.

Suggestions:

It is suggested that pointing may be undertaken of the structure. Similarly

masonry work may be undertaken from where masonry blocks are removed.

It is also suggested that on the crest of this structure, thick concave shape

concrete lining may be made to provide protection from the flood water, to the

crest portion.

125

K.T. Weir No.5


One outlet has been provided in this structure, which is permanently closed

by concrete diaphragm.

The scouring of the toe portion has occurred on the large scale exposing

the masonry used at the foundation [Fig. No. 176].

Suggestions:

It is suggested that as given in Chapter No. 5 downstream face of the K.T

weir may be modified giving ogee shape.

It is also suggested that thick concrete apron may be provided at the toe

portion up to some distance to avoid scouring of rock.

K.T. Weir No.6

Length: 16.8 m. Top Width - 0.56 m. Height - 0.63 m.

Two outlets have been provided in this but are permanently closed by

concrete diaphragm. Towards downstream of this structure, sheet jointed,

weathered amygdaloidal basalt is exposed. Due to removal of weathered

amygdaloidal basalt, during floods a shallow gully is formed in the nala.

Scouring of the foundation rock has occurred towards left of the structure.

[Fig. No. 177] similarly, pointing of the structure is removed at places and deep

notches are formed between two masonry blocks. Silting has occurred in the

submergence portion of this structure.

Suggestions:

It is suggested that on the crest of this structure, thick concave shaped


crest portion.

It is also suggested that pointing may be undertaken of the structure.

Similarly masonry work may be undertaken from where masonry blocks are

removed.

126

K.T. Weir No. 7


Two outlets have been provided. Originally both the outlets were closed up

to the crest of the weir. But subsequently a portion below the crest of the gates

was demolished in order to guide the floods from the portion of the outlets. In the

portion scouring has taken place-exposing masonry used in the foundation. [Fig.

No. 178]

Suggestions:

It is suggested that on the crest of this structure, thick concave shape

concrete lining may be spread to provide protection from the floodwater, to the

crest portion.

It is also suggested that pointing of the structure may be undertaken.


removed.

K.T. Weir No.8

Length -15.2 m. Top Width - 0.51 m. Height - 0.62 m

The scouring has taken place at the toe of the structure. Silting has also

occurred in the submergence area.

Suggestions:



crest portion.



removed.

K.T. Weir No.9


Two outlets have been provided out of which one outlet is permanently

closed by concrete diaphragm. At the toe, scouring has taken place.

127

Suggestions:


concrete lining may be made to provide protection from the floodwater, to the

crest portion.



removed.

K.T. Weir No.10

Length -12.5 m. Top Width - 0.6 m. Height - 1 m.

One outlet has been provided in the structure which is permanently closed

by concrete diaphragm. Scouring at the toe portion has occurred exposing

masonry used in the construction, almost excessive silting has taken place in the

submergence area.

Suggestion

It is suggested that on crest of this structure, thick concave shaped

concrete lining may be made to provide protection from the floodwater, to the

crest portion.

It is also suggested that pointing may be undertaken of the structure.


removed.

K.T. Weir No.11


Two outlets have been provided and were permanently closed by concrete

diaphragm but out of this, one diaphragm was found to be in broken condition.

Scouring at the toe portion has occurred exposing masonry used in the

construction, almost excessive silting has taken place in the submergence area.

[Fig. No. 179]

128

To meet the deficiency of water which is by supplied by canal for the

development of the area, 11 successive K.T. Weirs were constructed across

Ghagre nala to store rainwater. In every K.T. Weir outlets are provided to release

the flow of water in rainy season. These gates are supposed to be closed to store

water of late rains. But it was informed by the local people that gates of some K.T.

Weirs were not at all installed as in K. T. Weir Nos. 2, 4 and 8. In case of some

K.T. Weirs, these are permanently closed by constructing concrete diaphragm for

e.g. in 1, 3,5,6,7,9,10 and 11.

During the studies of the K.T. weirs, it was observed that water flows either

through outlets or through the body and foundation of the K.T. Weir. Therefore

water is not getting impounded in these structures.

To make the use of these structures, it is suggested that all the gates

should be properly fitted in K. T. Weir Nos. 2, 4 and 8. Similarly undertaking

repairs should stop leakage from the body of K.T. Weir and through the

foundation. So that, all the K.T. Weirs will act as check dams and water will

remain in these structures even during summer.

If possible, it is suggested that height of every K.T. Weir may be raised to

store maximum quantity of water, to overcome the deficiency of water through

canal.

5) Panoli Watershed Area, Dist. Ahemadnagar

As hill ranges occurring along the boundaries of the area have steep

slopes, rainwater drains out quickly without getting any time to recharge the

groundwater potential. Therefore area faces acute scarcity of water even for

drinking purpose.

Due to steep slopes on hill ranges and due to indiscriminate deforestation

extensive denudation of soil cover has occurred. [Fig. No. 77]

To avoid denudation of soil cover, structures for soil conservation have

been constructed at the higher reaches.

Similarly, to increase groundwater potential a large number of water

conservation structures have also been constructed in the area as given below. [Fig. No. 77]

129

Water Conservation Structures

Three percolation tanks have been constructed in the area.[ Fig. No. 77]

Percolation Tank No.1 is constructed close to S-W boundary of the area on

Stream No.1, Percolation Tank No. 2 is constructed on Stream No. 3 towards N E

side of the area and Percolation Tank No. 3 is constructed beyond the northern

boundary of the area.

Check dams

Two check dams have been constructed across streams and about 21

small nala bunds have been constructed across different streams.

Details of Percolation Tanks

Percolation Tank No.1 [Fig. No. 77]

It is constructed on Stream No.1, towards southwest corner of the

watershed area. Zilla Parishad, Ahmadnagar, built the tank in the year 73-74. The

capacity of percolation tank is 574 cubic m. and command area is about 121 Ha.

This P.T. has got large catchment area as it is constructed at the lower

level on Stream No.1 Therefore, water occurs in this percolation tank throughout

the year.

The rock occurring in the vicinity of Percolation Tank is jointed compact

basalt. This Percolation Tank is constructed in the middle portion of Compact

Basalt where joints are well exposed, which can be seen beyond the left abutment

at higher level. As Percolation Tank is located in the jointed portion of compact

basalt Flow No.1, water percolates through percolation tank and downstream

area get benefit of the percolated water beyond the southern boundary of

watershed area and the wells located in the area of Wadule village get the benefit

of percolated water. This percolation tank was constructed about 25 years ago

and due to which large silting has occurred in it.

Percolation Tank No. 2 [Fig. No. 77]

This Percolation Tank has been constructed towards North-East of Panoli.

The tank is across Dara Nala and is located in Survey Nos. 615 and 617. The

capacity of this tank is about 280 cubic m. and 40 hectare of land is under

irrigation.

130

This P.T is constructed on amygdaloidal top portion of Flow No. 1, the

junction between top portions of Flow No. 1 and overlying Flow No. 2 is exposed

just below the F. R. L.

As the foundation is taken on fresh unjointed amygdaloidal top portion of

Flow No. 1 water does not percolate through Percolation Tank. However when

water level reaches up to F. R. L., water percolates through the junction between

Flow Nos. 1 & 2 and weathered sheet jointed amygdaloidal top portion of Flow

No. 1 is occurring along the rim of reservoir area and some wells located on the

bank of the nala get benefit of percolated water.

Percolation Tank No. 3 [Fig. No. 77]

This tank is located at a distance of about 3 km from Panoli- Parner road,

towards north of watershed area close to Parner ghat. It was constructed in

1981 under E.G.S. The capacity of the Percolation Tank is 141.60 Cu. m. and

about 25.80 Ha. of land is under irrigation.

The foundation of this tank has been taken on hydrothermally altered

greenish top portion of the flow. The greenish top portion of the Flow No. 1 is

vividly exposed on Panoli - Parner ghat. [Fig. No. 78] Hydrothermally altered

greenish top portion of the flow is thick. Due to weathering, sheet jointing is

developed in the upper portion up to some depth. But at the lower level, greenish

amygdaloidal top portion of the flow occurs in fresh condition without development

of joints.

The foundation of this P. T. is taken on sheet jointed, highly permeable,

amygdaloidal portion of the same flow. Due to which the tank becomes empty

through sheet-jointed portion of the rock.

The wells located towards downstream of this tank, do not yield water, as

water is not retained in sheet jointed amygdaloidal basalt and also in the lower

unjointed fresh Amygdaloidal Basalt.

Check Dams

Check Dam No. 1

It is located near Gaothan, its dimensions are

Length - 26 m. Height - 2.75 m. Top Width - 0.93 m.

Width of stilling basin - 1.6 m

131

It is constructed in cement concrete, downstream wall of the check dam is

sloping while upstream face is nearly vertical. Towards the right bank of this check

dam, columnar jointed Compact Basalt is exposed. The nala course is slightly

meandering and erosion has taken place along the right bank. Heavy silting has

taken place in the check dam, scouring has also occurred on the downstream of

check dam . Check Dam becomes empty due to leakage through columnar jointed

Compact Basalt occurring below the foundation.

Check Dam No. 2

It is located near Mr. Gaikwad’ s farm in Gut no. 8. Its dimensions are

Length: 23 m. Height: 2.05 m. Top Width: 0.97m

Width of stilling basin: 1.6 m.

The rock occurring on both sides of this check dam is columnar jointed

Compact Basalt. As the nala has gentle slope, heavy silting has taken place on

upstream side.

6) Hiwre Bazar Watershed Area, Dist. Ahmadnagar

A Large number of Water Conservation structures have been constructed

in Hivre Bazar watershed area as given in Table No.36 to improve groundwater

potential. The present status and modifications and repairs required there in are

given below.

Structures Constructed For Water Conservation

1) Percolation Tanks

2) Concrete Check Dams

3) K. T. Weirs

4) Small Earthen Bunds

132

Table No. 36 : Details of Water Conservation Structures across streams at Hiwre Bazar Watershed Area.

Sr. No. Chainage in m.

Name of the Structure

Length in m.

Height in m.

No. of Outlets

1 300 KTW-1 15 1.5 3

2 525 KTW -2 80 2.5 4

3 825 KTW- 3 70 2.5 4

4 1050 KTW- 4 50 2.5 5

5 1380 P T- 1 900 11 Waste Weir

6 2092 C D- 1 50 3.5 --

7 2767 C D- 2 35 2.6 ---

8 2917 P T – 2 700 9.6 Waste Weir

9 3442 E B- 1 150 5 Waste Weir

10 3552 E B – 2 120 5 Waste Weir

11 3652 E B- 3 120 5 Waste Weir

12 3752 E B- 4 80 5 Waste Weir

13 3900 E B- 5 50 5 Waste Weir

14 4050 E B- 6 31 5 Waste Weir

15 4350 E B -7 31 5 Waste Weir

( K. T. W. - Kolhapur Type of Weir ; C.D. - Check Dam; P. T. - Percolation Tank ;

E. B. - Earthen Bund )

The present state of the conditions and modifications and repairs required

to undertake of these structures such as Percolation tanks, K. T. Weirs and Check

dams are given below.

1) Percolation Tanks: [Table No. 36 ; Fig. Nos. 95 and 96]

Two percolation tanks have been constructed in Hivre Bazar watershed area

having capacity of 53 TCM to store water across main nala. [Fig. No.180 and 181]

Both the PT’s have been constructed having wave breakers [Fig.No.181] on the

u/s face and the spillway at the sides. [Fig. No.180 and 182]

For Percolation Tanks No. 1, no spillway bar [Fig. No.180] has been

constructed owing to the occurrence of quite hard broadly spaced jointed rock, in

the portion of the outlet. However, for Percolation Tank No. 2, a masonry spillway

bar has been provided in the form of ogee shaped downstream face.

133

It was observed that Acacia trees are luxuriantly growing on the wall of the

Percolation Tank. [Fig. No.181] The roots of the tress are bound to penetrate the

wall of earthen structure and avenues will develop for seepage of water, which

may harm the stability of the Percolation Tanks. Therefore, it is suggested that on

priority basis these trees should be cut down.

2) Check Dams: [Table No. 36; Fig. Nos. 95 and 96]

Two check dams have been constructed on the plateau of the area towards

west of Hivre Bazar village.

Both the check dams have been constructed as per the specifications

having end still weir and wing walls. But it was observed that wing walls towards

downstream are short in length therefore floodwater may damage the adjacent

farms. [Fig. Nos. 183 and 184]

3) K. T. Weirs: [Table No. 36; Fig. Nos. 95 and 96]

Four K. T. Weirs have been constructed in series near northern boundary

of watershed area. These K. T. Weirs are as per the specifications. The number of

gates for the K. T. Weirs depends up on the length of the K. T. Weir. In K. T. Weir

No. 1, towards downstream concrete diaphragm has been provided touching the

toe of the rock. [Fig. No. 185] In K. T. Weir No. 2, erosion close to the downstream

part near the toe has taken place due to lack of apron of concreting touching the

toe [Fig. No.186] In case of K. T. Weir No. 3, toe portion has been left unprotected

for want of apron touching the toe. [Fig.No. 187]

4) Earthen Bunds: [Table No. 36; Fig. Nos. 95 and 96]

Seven earthen bunds have been constructed across the main nala. These

earthen bunds are as per the specifications such as outlet, stone pitching on u/s

and downstream faces. [Fig. No. 188]

Almost all the earthen bunds have been constructed on weathered, sheet

Jointed, permeable Amygdaloidal Basalt and water percolates from these bunds

towards and beyond the banks up to some distance. Therefore these water

conservation structures have helped in achieving considerable increase in the

water levels in the surrounding wells.

134

7) Hiwre Korda Watershed Area, Dist. Ahmadnagar

As mentioned in Chapter No. 2, nine check dams have been taken

constructed in the area of Hivre Korda watershed.[ Table No. 33;Fig. Nos. 106

and 107] At the time of visit, the construction work was in progress and functions

of the structures could not be seen. [Fig. No. 189] otherwise the state of the most

of water conservation structures was in good condition. In the higher reaches of

the valley, various soil and water conservation structures such as Continuous

Contour Trenches, [Fig.No.112] Staggered Contour Trenches, Gulley Plugs have

been constructed. [Fig. Nos. 191 and 192]

In the Check Dam No. 3, water had collected during the previous season

before the construction work was completed.

It was observed that on the downstream face of Check Dam No. 3, there

were signs of leakage through the wall in the form of deposition of CaCO3 on the

downstream face of the wall and growth of moss on it [Fig. No.192]. This indicates

that percolation was taking place through the junction between the two masonry

blocks owing to lack of supervision and quality of work. It is suggested that to

check the percolation necessary repairs should be undertaken immediately in

Check Dam No. 2, as large silting has taken place.

8) Kachhe Ghati watershed area

Measures Taken to Improve The Groundwater Conditions And to

Protect Soil Cover :

During the drought of 1972, Zilla Parishad, Aurangabad constructed one

Percolation Tank, One Check Dam. However, as per the information given by the

local people, this Percolation Tank had not given much relief to the area to

improve ground water conditions and the area felt acute scarcity of water till the

watershed development work was undertaken by Dilasa Janvikas Pratisthan,

Aurangabad in the year 1996 and the work was completed in 2000. During this

period, following structures were constructed for water and soil conservation in the

area.

135

Table No. 37 : Details of Water Conservation Structures Constructed In

Kachhe Ghati Watershed Area

Type of Structure Length

(m.)

Height

(m.)

Width

(m.)

Spread of water towards

u/s (m.)

# C.D. No.1 12.5 2.0 1.05 133

C.D. No.2 19.0 2.6 1.0 150

C.D. No.3 21.0 2.5 1.0 25

C.D. No.4 30.3 3.4 1.0 30

C.D. No.5 18.0 2.0 1.0 75

*E. B. No.1 40.0 3.8 1.3 --

E. B. No.2 60.0 3.6 1.6 --

E. B. No.3 50.0 3.2 1.5 --

E. B. No.4 53.0 3.4 1.55 --

# C. D. Check Dam, * E. B. Earthen Bund

The main purpose of this study is to determine influence of geological

conditions on the utility of Water Conservation Structures. Therefore, more

emphasis is given on determining the field and water bearing characters of the

rocks occurring in the submergence and beneficiary areas of these Water

Conservation Structures. For this purpose geological mapping of the area was

carried out. The details of Water Conservation structures constructed are given

below. [Fig. No. 118]

Check Dam No. 1

It was constructed by Z. P. Aurangabad in 1972 at Ch. 450 m from the

southern boundary of the watershed area. It is constructed by using stone

masonry. Its dimensions are

Length – 12.5 m. Height- 2 m. Width – 1.05 m.

Immediately towards u/s of this check dam Vesicular Amygdaloidal top

portion of the Flow No. 1 is exposed. Scouring has occurred in the apron

provided. The apron is almost separated from the foundation rock. [Fig. No. 193]

136

Suggestions

The cement concrete should be filled up at the undermined portion. End

still weir may be constructed at the end of the apron by taking its foundation at

deeper level. So that undermining at the end still weir would not occur, as energy

dissipater to prevent the kinetic energy of overflowing of water and it would

overflow from the structure.

Dilasa Janvikas Pratisthan, Aurangabad, constructed Check dam Nos. 2 to 5.

Check Dam No. 2

It is constructed at Ch. 740 m. by using stone masonry. Its dimensions are

Length – 19 m. Height- 2 .6 m. Width – 1 m. Immediately towards u/s of this check dam highly weathered hydrothermally

altered, purple coloured top portion of Flow No. 2 is exposed up to considerable

distance. Scouring has occurred in the apron provided towards d/s. The apron is

almost separated from the underlying rock.

While observing the structure it was felt that no quality control was

maintained in the work. Similarly, workmanship is also poor. At places pointing is

removed. The scouring of wing wall constructed towards downstream along the

right abutment has occurred at the base due to removal of masonry blocks. It is

due to insufficient length of the wing wall. The end still weir is also in the very bad

state of preservation. [Fig. No. 194]

As per the information given by the local people profuse leakages occur

through the foundation of Check dam No. 2, this indicates that foundation has

either been only up to shallow depth or no quality measures were taken while

taking the foundation.

Suggestions

1) The repairs of the end still weir may be undertaken by providing thin apron

of concrete.

2) Lining of the bottom portion of wing wall may be undertaken on priority

basis otherwise wing wall may collapse. Fresh pointing may be undertaken in the

body of the structure.

137

3) Towards downstream of the end still weir a deep trench may be taken and

it may be filled up by black cotton soil up to the depth of 1 m. from the surface.

This filled up trench may be properly compacted. The upper portion of the trench

may be filled by concrete to provide protection to the underlying black cotton soil.

The width of the proposed trench may be 2 m. so that no scouring of foundation of

the end still weir would occur.

4) To avoid percolation of water from the foundation of the Check Dam, a

deep cut off may be taken touching the u/s face of the Check dam and Black

Cotton Soil may be filled in it.

Check Dam No. 3

It is constructed at Ch. 1100 m. by using stone masonry. Its dimensions are

Length – 21 m. Height - 2 .5 m. Width – 1 m.

The farmers, having their farms close to this check dam have given the

information that leakages have developed from the foundation and in immediate

downstream water gets stagnated in the nala, in which waterweeds are growing

luxuriantly. [Fig. No. 195]

1) The repairs of the end still weir may be undertaken by providing thin apron

of concrete.

2) Lining of the bottom portion of wing wall may be undertaken on priority

basis otherwise wing wall may collapse. Fresh pointing may be undertaken

in the body of the structure.

3) Towards downstream of the end still weir a deep trench may be taken and

filled up by black cotton soil up to the depth of 1 m. from the surface. This

filled up trench may be properly compacted. The upper portion of the

trench may be filled by concrete to provide protection to the underlying

black cotton soil. The width of the trench may be 2 m. so that no scouring

of foundation of the end still weir would occur.

4) To avoid percolation of water from the foundation of the Check Dam, a

deep cut off may be taken touching the u/s face of the Check dam and it

may be filled by black cotton soil.

138

Check Dam No. 4

It is constructed at Ch. 1790 m. It is constructed by using stone masonry. Its

dimensions are

Length – 30. 3 m. Height- 3.4 m. Width – 1 m.

The foundation is taken on the junction between Flow Nos. 4 and 5. At the

foundation, weathered Amygdaloidal Basalt is occurring, therefore water

percolates through it. Though this check dam appears in good condition [Fig. No.

196] from the downstream face of it water is oozing out from the joints of

masonry. [Fig. No.197] This indicates lack of supervision during the construction

work.

Suggestions

It is suggested that complete pointing of the downstream face may be

undertaken. Similarly, in summer when water level goes down and entire check

dam becomes empty, pointing in the u/s surface of the check dam may be

undertaken.

Check Dam No. 5

It is constructed at Ch. 3800 m. It is constructed by using stone masonry.

Its dimensions are

Length – 18 m. Height- 2 m. Width – 1 m.

Check Dam No. 5 is constructed on amygdaloidal top portion of Flow No 5.

At the time of visit due to torrential rains water had collected in this Check dam. In

general it is in good condition [Fig. No.198] However, the end of the apron

towards downstream is damaged due to flow of water. [Fig. No.199] It was

observed that apron is not anchored into the underlying rock and due to erosion a

gap has developed at the bottom of the apron.

Suggestions

The undermined portion of the apron should be filled up by cement

concrete. End still weir may be constructed at the end of the apron by taking its

foundation at deeper level. So that undermining of end still weir will be stopped

and it will also act as energy dissipater to prevent the kinetic energy of overflowing

water.

139

Percolation Tank

It was constructed by Minor Irrigation Division of Z. P. Aurangabad during

the drought of 1972. It is located at Ch. 1560 m. Its dimensions are

Length – 370 m. Height- 15 m. Top Width – 1.25 m.

In the region of Percolation Tank, Jointed Compact Basalt Flow No. 4 is

exposed. It becomes empty at the end of February which indicates that

percolating conditions are favourable at the site of P. T. As such the stored water

adequately percolates before the onset of the summer hence, water does not

stand for evaporation during summer.

Immediately after the construction of this tank the downstream region had

been benefited. But in due course of time silting is taking place in the Percolation

Tank and rate of percolation has rather decreased

After the construction of Percolation tank no maintenance work was

carried out. Pitching is dislodged from the u/s slope of the Percolation tank. Trees

have grown luxuriantly on the Percolation tank. [Fig. No.200] as a part of

maintenance works these trees may be uprooted and new pitching may be made

to avoid scouring due to wave action of water. [Fig. No. 201]

Earthen Bunds: ( E. B.)

Four earthen bunds have been constructed much at the higher level on

steep slope towards u/s of last check dam i. e C. D. No. 5. These are also

constructed across small streams that are originating from the N -E side of

watershed area, which eventually meets the main nala at the end of d/s.

Earthen Bund No. 1

It is constructed at Ch. 3900 m. with following dimensions :

Length – 40 m. Height- 3.8 m. Top Width – 1.30 m.

In the submergence area of this bund, Spheriodally Weathered Compact

Basalt is exposed which is clearly seen in the cut occurring on the bank of the

nala. [Fig. No. 141]

140

As percolating conditions are favourable due to occurrence of Spheriodally

Weathered Compact Basalt in the submergence area, downstream area gets

benefit from this bund.

Earthen Bund No. 2

It is constructed at Ch. 4200 m. having dimensions :

Length – 60 m. Height- 3.6 m. Top Width – 1.60 m

As this earthen bund is constructed on steep slope, water gets filled up in it

to F. R. L. during rainy season and water flows through the waste weir.

Earthen Bund No. 3:

It is constructed at about Ch. 4325 m. Its dimensions are


This earthen bund is constructed immediately towards u/s of E. B. No.2,

therefore, back water of E. B. No. 2 almost touches the toe of this bund.


Basalt is exposed through which percolated water merges into the reservoir of

E.B. No. 2, the wells taken close to the left bank get benefit from this bund.

Earthen Bund No. 4

It is constructed at Ch. 4400 m. Its dimensions are



Basalt is exposed. Therefore it provides suitable condition for percolation of water.

Along the tail Channel, Spheriodally Weathered Compact Basalt is exposed. But

as spheroids are large and weathering around every spheroid is thin, no erosion

of tail channel has taken place.

9) Kadwanchi Watershed Area

1) Structures Constructed Across Main Valley

Nine major check dams and one K.T. weir [Table No.17] have been

constructed across the main nala. In addition to these, 10 small check dams have

been constructed across the tributaries, meeting the main nala.

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The present state of conditions and suggestions for repairs of these

structures are given below serially. The numbers to these structures are serially

from u/s to d/s. However they are described below serially from downstream to

u/s.

Major Check Dam No.9

Towards u/s, wing wall constructed towards left bank is very much

damaged and collapsed. Highly weathered rock is exposed on which wing wall

has been constructed.

It was noticed that instead of construction of such thick wing, thin wing wall

would have served the purpose. On removal of thin coat of concrete, masonry had

dislodged from the wall. [Fig. No. 202]

Suggestions:

It is likely that in due course of time, during heavy floods the entire coat of

concrete would collapse and outflanking may occur from the left side of the check

dam.

Therefore it is suggested that, a masonry wing wall with cement mortar

having sufficient length may be constructed to avoid outflanking.

Major Check Dam No. 8

The wing wall constructed towards downstream on bank has almost

collapsed exposing highly weathered Amygdaloidal Basalt, on which walls were

constructed. During heavy floods when Check dam would start overflowing, it is

likely that entire wing wall may get washed away [Fig. No. 203] moreover scouring

of stilling basin has also occurred.

Suggestions

It is suggested that weathered Amygdaloidal Basalt may be excavated upto

required depth i.e. till fresh Amygdaloidal Basalt would be met with and by making

proper anchorage, a wing wall of concrete or masonry may be constructed upto

desired length.

The stilling basin needs to be repaired. The coat of concrete may be

provided towards downstream to cover weathered Amygdaloidal Basalt.

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Though wing walls are intact, scouring of end portion of apron constructed

towards downstream is damaged and undermining has occurred [Fig. No. 204 ]

Suggestions

The undermined portion and the apron may be filled up with cement

concrete. End still weir may be constructed at the end of the apron by taking its

foundation at the deeper level. So that undermining of the end still weir would not

occur and it would act as energy dissipater to prevent kinetic energy of flowing

water from the structure.


Suggestion

Similar to check dam Nos. 7 and 8, towards d/s, wing wall has been very

much damaged due to impact of floods. It is suggested that new thick wing wall of

concrete or masonry having sufficient length may be constructed.


It is in good condition.


Heavy silting [Fig No.205] has taken place in this the reservoir area

reducing its storage capacity to store designed quantity of water.

Suggestion

Similar to Major Check Dam No.4, almost in all the water conservation

structures silting has taken place. It is suggested that silt may be removed during

every summer season, before the onset of the monsoon.

K.T.Weir

As it is constructed much prior to the development activity undertaken by

M.S.S.M. The upper gates were not at all installed after the construction.

Therefore water could not get stored in the K.T. weir up to its full capacity [Fig.

No. 206]

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Suggestions

It is suggested that repairs of K.T. Weir may be undertaken meticulously

and gates may be installed to make the use of K.T. Weir for storing floods of late

rains.

The K.T. Weir may be handed over to the Gram Panchayat for its further

maintenance.

Major Check Dam Nos. 3 and 2

These are in good condition.

Major Check Dam No.1

Immediately towards downstream of end still weir, closely spaced jointed

spheroidally weathered Compact Basalt is occurring. As every spheroid occurs

almost as loose rock, during the floods scouring of the foundation of end still weir

will take place. It is observed that heavy silting has taken place in Check Dam No.

1. [Fig. No.207] the bed of the nala is also covered by bushes which binds the silt

through spreading of roots.

Suggestion

1) Due to occurrence of spheroidally weathered Compact Basalt, erosion

towards downstream of end still weir may take place. Therefore it is suggested

that the bed of the nala towards downstream of the end still weir may be covered

by concrete up to required distance.

2) It is also suggested that desilting and removal of bushes may be

undertaken during pre monsoon period.

2) Structures Constructed Across Tributaries

Small Check Dam No. T- 8

Towards the u/s of this small check dam, highly weathered amygdaloidal

basalt is exposed on the banks of the tributary. After the water column was

created in the structure, the weathered murum started collapsing in the bed of the

tributary and thereby reducing its storage capacity.

It is likely that outflanking may occur due to collapsing of highly weathered

amygdaloidal basalt from the abutment portion.

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Suggestions

1) Towards u/s, wing walls of the adequate length may be constructed to

avoid outflanking.

2) The Vertical natural cuts occurring on the banks of the tributary may be

dressed to stabilize the portion of banks.

Small Check Dam No. T- 7

Although wing walls have been constructed towards u/s their lengths are

inadequate. Due to which, it is likely that outflanking may occur due to collapsing

of highly weathered Amygdaloidal Basalt from the abutment portion.

Suggestions

1) It is suggested that, the length of the wing walls may be extended at least

by 5 m. towards u/s to avoid out flanking.

2) As mentioned above, the banks of the tributary may be dressed to stabilize

the portion of the banks.

Utility of Water Conservation Structures from Structural point of View

As mentioned above, four types of Water conservation Structures viz. K. T.

Weirs, Check Dams, Percolation Tanks and Earthen Bunds have been

constructed in 9 watershed areas within the span of study. Their utility from

structural point of view is described below.

A) K.T. Weirs

K.T. weirs are constructed to store water of late rains. Therefore, their

gates are installed by 15th October and gates are removed before the onset of the

next monsoon to pass floods after heavy showers. But it was noticed that the

timetable of operation of the gates is not generally followed.

Following shortcomings were revealed in the K.T. weirs constructed in

watershed areas.

1) Undersized Gates:

In case of K.T. Weir No.1 in Nashera , the gates were lying in abeyance

,as the width of gates is less than the distance between the two channels of the

outlets. The gates are brought to the site but not fitted in the K.T. weir and were

145

left either on the bed or on the banks of the nala. The gates which are lying on the

bed of the nala are either washed away along with the flood or may be rusted.

2) No gates are fitted:

In Kadwanchi watershed area, upper gates of the K.T. weir are not at all

fitted. Therefore K.T. weir does not get filled upto its full capacity.[Fig. No. 206]

3) Gates are stuck up in the channel:

It was also observed that, in case of some K.T. weirs the gates are jammed

and stuck up in the channel due to which they could not be removed before the

onset of monsoon. Therefore outflanking of floodwater also occurs damaging the

adjacent cultivated area, viz. K.T. Weir No. 2 and 3 in Nashera [Fig. No. 159]

4) Total silting of K.T. Weirs:

Similarly in case of some K.T. weirs due to permanent closing down of the

gates, excessive silting has occurred even up to the crest of the K.T.Weir viz.

K.T.weir Nos. 2 and 3 in Nashera same is the case with all K.T. Weirs constructed

in Mahatma Phule and Jai Yogeshwar Societies in Ozar,Dist .Nashik [Fig. Nos.

49 and 50]

5) Erosion at the toe of K.T. Weir and removal of masonry blocks:

As gates are permanently fitted, water from the K.T weir falls from its crest

in its toe region like a waterfall creating erosion of country rock and damaging the

construction work of the K.T. weir viz. K.T. weir No. 3 at Nashera, K.T weir Nos. 1

and 4 in Ashewadi, .[Fig. No. 161] K.T. weir Nos. 1,2,5 and 6 Mahatma Phule,

K.T. weir Nos. 2,3,5,7,8,9,10 and 11 in Jai Yogeshwar area and a K.T. weir in

Kadwanchi area.

6) Outflanking from the K.T. weirs:

In case of some K.T. Weirs, they are not properly anchored into the

abutment area and no wing walls have been constructed. Due to which during

high floods outflanking occurs (viz. K.T. weir No. 8 in Kadwanchi) by washing

away the cultivated land in the adjacent area. viz. K.T. Weir Nos. 2, 4 and in

Ashewadi,[Fig. No.163] and all K.T. weirs in Mahatma Phule and Jai Yogeshwar

societies.

146

7) Formation of Gullies and waterfall in the downstream portion:

As in case of some K. T. Weirs weathered rock is occurring in vicinity and

due to lack of concrete apron towards downstream portion waterfall has

developed. Viz. K. T. weir Nos. 1,4,6 and 7 of Ashewadi, 3 and 5 in Mahatma

Phule Society, and 6 in Jai Yogeshwar Society.

8) Lack of maintenance of the rubber packers:

In case of K.T. weir No. 3 in Nashera, the stored water comes out forcefully

through the channels of the K.T weir due to lack of maintenance of the rubber

packers came out.

9) Lack of modification in the structure:

In case of Mahatma Phule and Jai Yogeshwar societies, outlets of the K.T.

weir are permanently closed by constructing concrete diaphragm so that K.T.

weirs would act as storage structure like check dam. However, no modifications in

the K.T. weir have been made to allow the flow of water without damaging toe

portion of K.T. weir. Therefore, extensive erosion has taken place at the toe

portion there by undermining of foundation of the K.T. weir. As a result in K.T.

Weir No. 2 in Hivre Bazar area, water rushes out through the undermined portions

of the K.T weir.

B) Check Dams (C. D. )

Masonry check dams have been constructed in large numbers in all

watershed areas studied. Every check dam gets filled up to its rim and excess

water which could not be stored in the check dam and passes towards

downstream over the crest of Check dams. But no elaborate energy dissipation

arrangements have been made in all the check dams.

1) Flat surface of the crest:

Instead of giving convex shape to the check dams the crest of each and

every dam is flat. Due to which water overflows from the check dams and falls

towards downstream getting some trajectory. Due to impact of falling water, thin

coat of cement plaster provided on the flat surface of the crest has been washed

away exposing inner masonry blocks. In case of some check dams, even the

masonry blocks from the crest are dislodged.

147

2) Lack of ogee shape downstream face:

To every overflow structure, its downstream face is given ogee shape so

that water passes over the crest will falls down towards downstream touching the

surface of the overflow structure. But in all the check dams so constructed the

downstream face has been given a slope of 1: 0.25. Therefore, some flood water

directly colloids on the rock occurring close to the toe of the structure causing

erosion of the rock therein.

3) Lack of concrete lining on the downstream surface of the wall :

Similarly, on the downstream face of the structure no lining of concrete has

been laid.. Masonry blocks are exposed on the downstream face of check dam.

Due to impact of the falling of water, pointing around the masonry blocks are

removed developing deep gaps between them, as a result masonry blocks have

become loose. Viz. C. D. No. 5 in Kachhe Ghati [ Fig. Nos. 47 and 199], C. D. No.

9 in Kadwanchi { Fig. No. 202]

4) Inadequate width and depth of the bucket at the toe:

Except at a few check dams, bucket has been provided at the toe.

However the depth and width of the bucket is very small. Therefore these buckets

do not serve the purpose of dissipating the kinetic energy of water. Therefore it is

suggested that deep and broad buckets may be provided at the toe of all the

check dams. Viz. C. D. Nos. 1 and 2 in Kachhe Ghati.

5) Inadequate height and lack of anchorage of the end still weir:

Wherever buckets are constructed they have been provided with very short

wall to act as end still weir. However these walls have been constructed without

taking foundation on the underlying fresh rock. Due to which almost undermining

of end still weirs have occurred. It is suggested that its foundation should be

anchored in underlying hard rock and by keeping sufficient height over the

surface. Viz. C. D. Nos. 1[Fig. No. 193] C. D.Nos. 2 and 5 in Kachhe Ghati [Fig.

Nos 194 and 199] and C. D. Nos.7 and 8 in Kadwanchi[Fig. Nos. 203 and 204]

6) Leakage through the body of the check dam:

It is observed that in case of some check dams, leakages have developed

through the pointing of the wall. Due to continuous leakage through the body,

148

large voids would be created removing masonry blocks leading to profuse

leakage. Viz. C. D. No.3 [Fig. No. 190] in Hivre Korda, C.D. Nos. 3 and 4 in

Kachhe Ghati.[ Fig. Nos. 195 and 197]

7) Lack of anchorage of end portion:

It is observed that in almost all the check dams the ends of the check dams

are merely abutted on the adjacent weathered rock without providing proper

anchorage in the abutment rock up to sufficient depth.

8) Inadequate length of the wing walls:

It is also observed in majority of the check dams that wing walls towards

u/s and downstream have very short length, due to which outflanking has

occurred in some check dams and adjacent cultivated land has been washed out.

Similarly, the floods that have spread from the check dams have damaged

the cultivated land beyond the banks of the nala towards d/s. Viz. C. D. Nos. 1and

2 in Hivre Bazar, [Fig. No. 183 and 184], C. D. No. 2 in Kachhe Ghati.[ Fig. No.

194] C. D. Nos. 6 & 8 in Kadwanchi [Fig. No. 203]

9) Excessive silting:

In almost all the check dams, heavy silting has occurred reducing the

storage capacity of the structures. Due to deposition of the silt, waterweeds have

grown in some check dams. Viz. C. D. Nos.1, 2 in Panoli, 2 in Hivre Korda C. D.

Nos. 1 and 4 in Kadwanchi [Fig. Nos. 207 and 205 respectively.]

10) Side collapses of the bank of the nala:

It was also observed that towards u/s when water gets stored in the check

dams, the sides of the banks have found to be collapsed. Therefore, it is

necessary to stabilize the banks by giving gentle slopes up to the end of

submergence area.

Percolation Tanks and Earthen Bunds

Percolation tanks (P. T.) and Earthen Bunds (E. B.) have been constructed

in some watershed areas. P. T’s have been constructed by Z.P. across the major

nalas much prior to the area having been taken up for the development by

developing agency. Where as earthen bunds have been constructed by the

149

development agency in large number across the small tributaries existing in the

watershed areas.

C) Earthen Bunds ( E. B.)

Lack of adapting technical norms in the construction of E.B

It was observed that the E.B.’s seem to have not been constructed by following

the technical norms, merely some earthen bunds have been constructed dumping

loose soil on the bed of the tributary either without any compaction or providing

proper zoning. viz. All E. B.’s in Ashewadi area.[ Fig. Nos. 170 and 171]

In some earthen bunds, neither pitching has been provided nor they are

kinked into the abutments slopes by taking trenches on u/s & downstream slopes.

e.g. All E. B.’s in Ashewadi area.

D) Percolation Tanks

In most of the percolation tanks it was observed that pitching on u/s &

downstream faces are dislodged by erosion thereby exposing material used for

the construction of P. T. viz. P. T. In Kachhe Ghati [Fig. No. 201]

It was also observed that on the wall of the P. T.’s large trees are growing

in profusion. The roots of these trees in due course of time may create cracks and

voids in the wall causing profuse leakage. viz. P. T. In Hivre Bazar and Kachhe

Ghati[ Fig. Nos. 181 and 200]

It was also observed that heavy silting has occurred in P.T.’s creating

impervious blanket in the reservoir portion due to which percolation is totally

hampered and the stored water in the P.T. is left behind only to be lost by the way

of evaporation without giving benefit to the downstream region. [Fig. No. 200]

Recommendations for the modification of water Conservation Structures. In all the check dams so far constructed in watershed areas studied, no

energy dissipation arrangements have been provided. The check dams have

been constructed similar to the masonry compound walls. [Fig, No. 208] Ideally

every structure should have curviform crest, ogee shape downstream face and

broad deep bucket with end still weir at the front. [Fig.No.209] But such

configuration has not been adapted in the existing check dams.

150

Therefore, to avoid erosion of the rock at the toe, all these check dams

require suitable modifications to achieve energy dissipation. Following simple

modifications are suggested without making much alteration in the original

structures.

A) The downstream face of the check dams may be modified in such a way

that it would acquire ogee shape with broad and deep bucket in front of the toe

and at the end still weir [Fig.No.210] But for such modification, much alteration

would be required and it would be a costly proposition. Moreover, there would

also be problem in creating proper bond between the wall of the check dam and

the new masonry work. Therefore instead of going for costly affair following

modification may be adapted.

B) Touching the downstream face of the check dam, rather broad masonry

steps may be constructed in a series so as to dissipate gradually and

successively kinetic energy of the flow of water to arrest the erosion in the toe

portion of the check dam. [Fig.No.211]

Again in case of K.T. Weir where gates are permanently closed, similar

arrangements may be made for energy dissipation to avoid erosion of the rock at

the toe portion.

C) Alternatively, at the toe of KT Weir and also at the toe of check dams a

thick apron of rich concrete extending much towards downstream may be

provided to avoid erosion of the rock. [Fig.No.212]

Maintenance of the Water Conservation Structures Constructed

After the construction of water conservation structures, it seems that they

have been not been paid due attention by the local people and also by developing

agency Eventually much needed maintenance measures were overlooked

causing dilapidation of the structures. Therefore it is suggested that some funds

may be reserved for the maintenance from time to time. During the work of

construction itself, maintenance should be initiated simultaneously and local

artisans may be trained to undertake minor repairs of the structures.

Subsequently, the maintenance work should be entrusted to the local

Grampanchayat.

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