Volume: VI Chapter: 3 Page No: 9

Comprehensive CAT Plan of Satluj River Basin

Chapter 3:

Physical and Biotic factors

The total area of the Si Sub catchment is 32060 Ha. The Si Sub

catchment has varied landforms, forest types, rainfall patterns,

agro-ecological zones and soil types. This chapter gives an

overview of the Si Sub catchment. The description of each

parameter can be found in the Technical mapping chapter of this

report.

1. Landforms

The Landforms of Si Sub-

catchment represents that

Si sub catchment has two

types of landforms viz

Steep to very steep high

hills of Lesser Himalayas

and Fluvial valleys. It is

observed that maximum

area i.e. 96% of the Si sub

catchment is covered by Steep to very steep high hills of Lesser

Himalayas while only 4% area is covered with Fluvial valleys.

2. Forest types

The forest types that are present in the Si Sub-catchment shows

that the area under Si Sub-catchment has 2 types of forests viz

Sub tropical broad leaved hill forest and Sub-tropical pine forest.

It is evident that 72% area of this Sub catchment is occupied by

Sub tropical broad leaved

hill forest while 28% area

is under Sub tropical pine

forest.

3. Rainfall

The pie diagram shows

that the Si Sub catchment

receives good rainfall. It is

evident that Si sub

catchment receives rainfall

that has 3 ranges viz

1000-1500mm, 1500-

2000mm and >2000mm. It

is can be noted that

maximum area i.e. 70% of

the Si sub catchment receives rainfall that exceeds

2000mm.Whereas 26% area receives rainfall in the range of

1500-2000mm and merely 4% of the area receives rainfall in the

range of 1000-1500mm.

Volume: VI Chapter: 3 Page No: 10

Comprehensive CAT Plan of Satluj River Basin

4. Agro-ecological zones

Agro-ecological zones of Si

Sub-catchment show that

the Si Sub catchment has 2

types of Agro-ecological

zones. The maximum area

i.e. 99% of this Sub

catchment is under the

Agro-ecological zone

described as Warm, Perhumid, Lesser Himalayas with 270-300

days LGP while only 1% area is under the Agro-ecological zone

described as Humid/Perhumid, Lesser Himalayas with 300-330

LGP.

5. Soil types

The soil types present in the

Si Sub-catchment vary

greatly. The Si sub

catchment has

heterogeneous soil with 5

different soil types. The

diagram drawn below shows

the distribution of different

soil types in the Si Sub-

catchment.

Note: The name of each soil types being very descriptive, we have denoted them

as Soil types units. This nomenclature is used in the above diagram and also in

the further explanation. The description of the soil types is presented in the table

given below in table A.

The Soil types 49, 55 and 60 occupy nearly the same area in this

Sub catchment where Soil type 49 is present in 29% of the Sub

catchment area. Whereas Soil types 55 and 60 occupy 33% and

31% area respectively. In addition, Soil types 37 and 27 cover

5% and 2% area respectively.

Table A: Soil type description

Soil Description

Soil

type

unit

Shallow, somewhat excessively drained, mesic, coarse-loamy soils on

moderate slopes with loamy surface and severe drained, fine-loamy

soils with loamy surface and severe erosion. 27

Shallow, somewhat excessively drained, thermic, loamy-skeletal soils on moderately steep slopes with loamy surface. Severe erosion and strong stoniness, associated erosion and strong stoniness, associated with Rock outcrops. 37

Medium deep, well drained, thermic, fine loamy soils on moderately steep slopes with loamy surface, severe erosion and slight stoniness, associated with Shallow, well drained, fine-loamy soils with loamy surface and moderate erosion. 49

Deep, well drained, thermic, fine-loamy soils on moderate slopes with loamy surface and moderate erosion, associated with Medium deep, well drained. Loamy-skeletal soils with loamy surface and severe erosion. 55

Medium deep, well drained, thermic, fine- loamy soils on moderate slopes with loamy surface and severe erosion, associated Shallow, well drained, coarse-loamy soils with loamy surface, severe erosion and slight stoniness. 60