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GEOLOGY

The Geological Survey of Pakistan has not yet surveyed the area for detailed geo-physical interpretation, however, a team from the Centre of Excellence in Geology, University of Peshawar has conducted a survey. According to their report the rock types between Besham and Komila comprise of Besham group, Dubair grandodiorite, Jijail ultranaties, Pattan Garnet and the Komila Amphibolites.

 Besham group

These include metasediments, which are divided into biotic psanamitic metasediments, graphitic medasediments, graphitic metasediments and amphibolitic from mafic intrusions.

 Jijal ultramifics

These rocks are exposed for about 8 km north of Jijal. The most common rock type is pyroxenite; dunite and periodtite are less abundant. Present mineralogy appears to be metamorphic and to reflect conditions around 800-850 Co. The important minerals are plagioclase, garnet, chinopyroxene and Quartz. There is approximate transition from perioditites to garnet, garnet granulites continue until Pattan. Most of these rocks contain plagioclase and are derived from mafic to intermediate compositions.

 Komila/Dassu

This is a complex terrain of amphibolitc, layered mafic complex largely of morite composition and mineralogy, multiple granitic intrusions of both pre and post tectonic character and volcanic rocks. Along Pattan stream a few meters thick calcarious horizon comprises mainly of quartz, plagiclase, grossular garnet and calcite associates the amphibolites can be found. The banded aspect and the association of metasedimentary rocks lead the previous workers to regard the banded amphibolites of the area to be meta-sedimentary. The medium to course grained and non-bounded amphibolities, on the other hand, clearly seem in many cases to be igneous parantage, probably basic intrusions in main, because:

 a.       in places they contain xenoliths of fine grained amphibolites;

b.       they locally cut across the banded types, and

c.       their outcrops are irregular in outlines; although most of them are concordant, they may not extend for long distances along the general trend of the  bending despite their large sizes in some cases. Most of these rocks are gneissore and dioritic looking, but a few are mela-nocratic.

 Some of the amphibolities in the Indus Valley have a very high proportion of hornblende at places to the near exclusion of other minerals. It appears that metamorphism has played an important role in the development of such hornblende rich rocks.

CLIMATIC FEATURES

Kohistan is comprised of mountains and the hilly agricultural regions. The low altitude (below 900m) in Kohistan get very hot in summer and extremely cold in winter season. In the higher regions, weather remains pleasant in summer. Due to the intensive snowfall, travelling to and from the valleys can remain restricted in winter.

PHYSICAL FEATURES OF PALAS

LOCATION OF PALAS

The Palas Valley is located on the left bank of the river Indus falling under the jurisdiction of Tehsil Palas and Kohistan Forest Division. The locality of the tract varies from 34°-52' to 35°-16' north latitude and 72°-52' to 73°-35' east latitude. It is bounded on the north and north-east by Jalkot valley, on the east by Kaghan, on the south by Allai and on the West by the river Indus.

The tract covers an area of 1300 km2 and is a sub-watershed of the river Indus. The area (within the project area) is drained by two main nullahs; namely Musha’ga and Sherakot, which flow into the river Indus near Keyal and Pattan respectively.  

The entire tract is a series of rugged mountains with elevations ranging from 600 to 5151 meter above mean sea level (AMSL). The topography of the area is rough with bare out-crops and desolate precipitous slopes breaking the continuity of the forests. Moderate slopes and flat pans are found near in the valley and are usually locations of habitations like Sherakot, Sheryal and Pichmuro.

GEOLOGY

Earthquakes

The geology of the area is extremely complex. Pattan, at the western boundary of Palas, was at the epicentre of a major earthquake in 1974, which reportedly killed thousands of people in District Kohistan including Palas. According to Ives and Messerli 1989, Earthquakes may also accelerate siltation in the area.

CLIMATIC FEATURES

The tract experiences both dry sub tropical (below 5,000ft MASL) and temperate type of climate (5000ft+MASL). The area lies on the transitional belt between the Trans-Indus tract in the North-West and Moist Temperate valley of Kaghan in the South-East. Winter starts from early November with the first snow fall on higher peaks and lasts till March. During these months the temperature falls below zero degrees centigrade. A major portion of precipitation is received in the form of snow. Summers inside the valley are pleasant while heat and humidity below 3000 feet altitude is experienced. No meteorological observatory, so far, has been established in the area; however, data recorded at Besham and Naran observatories, having close resemblance with the climate of the Palas area, are available (see tables 4-6 below).

Kolai and Batera forests receive maximum of monsoon rainfall which decreases as winds travel towards 'North-east, due to mountain barriers.  

Average monthly precipitation

May to June and September to October are the driest months. Winter rains are mainly due to western disturbances from the Mediterranean Sea and the bulk of it is received during February to April. Flash floods occur in July and August which can cause moderate to severe damage to agriculture lands, infrastructure including inhabitations, roads and bridges. 

Table 4:     Average monthly precipitation

Month

Besham

Naran

January

64.52

91.44

February

194.13

123.44

March

337.06

112.01

April

255.78

101.85

May

90.17

51.56

June

25.65

50.29

July

58.42

128.77

August

38.10

123.19

September

1.98

94.23

October

92.20

57.65

November

49.02

19.05

December

77.47

54.86

Average Monthly temperature

The temperature rises rapidly from June onwards until the monsoon season when there is a slight fall in the temperature. The months of December and January experience a severe drop in the temperature, and in areas above 1818 meter the temperature falls below zero degree centigrade. Severe frost occurs during these months often damaging budding plants such as apple, pear and cherry.

 Average Monthly Temperature in Besham and Naran

Months

Besham

Naran

Max.

Min.

Max.

Min.

January

14.4

5.6

3.3

(-) 6.9

February

16.1

6.7

4.4

 (-) 5.8

March

22.2

11.1

7.2

(-) 2.8

April

27.8

16.1

4.1

1.1

May

33.9

20.0

18.1

8.7

June

38.8

22.8

24.8

12.0

July

36.7

24.4

25.0

10.6

August

34.4

23.3

25.6

12.6

September

33.3

20.0

20.5

9.6

October

30.6

15.6

17.0

 (-) 0.6

November

25.6

21.7

11.3

(-) 2.2

December

18.3

7.8

6.8

(-) 4.4

 The table below shows the humidity levels in the region.

 Monthly average relative humidity

Months

Chilas

Naran

0800 Hrs

1700 Hrs

0800 Hrs

1700 Hrs

January

64

18

64

68

February

60

32

75

70

March

53

27

70

71

April

45

24

69

68

May

37

19

58

-

June

28

14

45

39

July

34

17

49

47

August

41

20

65

53

September

37

18

62

4

October

36

21

60

5

November

44

24

71

6

December

55

33

61

6

 Floods

In September 1992, parts of NWFP, including Palas Valley experienced unprecedented heavy rainfall, with an estimated half the annual precipitation falling in a three day period. It is roughly estimated that the Palas River eroded approximately one million tonnes of rock and earth in a few days. 

 Damages were mostly confined to the valley floor (the forested slopes were mostly unscathed) in Bar Palas.  Two people died and two villages were almost entirely destroyed and many houses were also damaged or ruined.

 All foot-bridges and a 40 km stretch of the principle Bar Palas footpath were destroyed.  The destruction of bridges and paths doubled journey times, halved the portable load, interrupted herding of livestock and exacerbated local grazing pressures.  It greatly added to women's burden of work, which includes carriage of foodstuff and domestic possessions, collection of forest products and herding.  Temporary bridges and some paths have since been re-built by the local people.  However, traditional cantilever structures are no longer adequate where floods widened the valley floor, and are now more vulnerable than before to seasonal floods; indeed, renewed floods in 1993 and 1994 destroyed most rebuilt bridges.

 The floods damaged and/or destroyed almost every irrigation channel in Bar Palas.  Channels with their in-take on the main river (Musha'ga) or main tributaries suffered most damage.  The deepening of valley floors destroyed in-takes, while erosion undermined many channels.

 Twenty-eight (70%) of the 40 watermills of Bar Palas were destroyed, together with their intakes, races, and in many cases the entire locality.  Villagers, predominantly women consequently had to trek long distances carrying heavy loads of grain and flour, to and from remaining mills.

 Since the floods of 1992, parts of the main Bar Palas footpath are still not suitable for pack animals.