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Chapter 3: Physical and Biotic factors The total area of the Sj Sub catchment is 36454 Ha. It is observed that the Sj Sub catchment has varied landforms, forest types, rainfall patterns, agro-ecological zones and soil types. This chapter gives a brief account of the physiography of the Sj Sub catchment. The detail description of each parameter can be found in the Technical mapping chapter of this report.
tropical broad leaved hill forest and Sub-tropical pine forest. It is evident from the pie diagram that Sub-tropical broad leaved hill forest and Sub-tropical pine forest cover nearly the same area in this Sub catchment. It can also be noted that Himalayan moist temperate forests are present over only 3% area of the Sub catchment. 3. Rainfall
1. Landforms The landforms observed in the Sj Sub catchment shows that the Sj sub catchment has two types of landforms in its entire area. These landforms are Steep to very steep high hills of Lesser Himalayas and Fluvial valleys which cover 55% and 45% areas respectively of the Sj Sub catchment. 2. Forest types The forest types that are present in the Sj Subcatchment represented in the pie diagram shows that the area under Sj Sub-catchment has 3 types of forests viz Himalayan moist temperate forest, Sub-
A graphical representation of the various rainfall intensities observed in the Sj Sub catchment through the pie diagram shows that most area of the Sj Sub catchment receives rainfall that has moderate intensity. It is apparent that Sj sub catchment receives rainfall that has 3 ranges viz 1000-1500 mm, 1500-2000 mm and >2000 mm. It is can be noted that 47% area of the Sj sub catchment receives rainfall in the range of 1500-2000 mm while rainfall greater than 2000 mm is observed in 40% of the area. Moreover, 13% area receives rainfall in the range of 1000-1500 mm. 4. Agro-ecological zones A graphical representation of the various Agro-ecological zones observed in the Sj Sub catchment shows that the Sj Sub catchment has two types Comprehensive CAT Plan of Satluj River Basin
Volume: VII Chapter: 3 Page No:
of Agro-ecological zone in its entire area. The Agro-ecological zone described as Warm, Perhumid, Lesser Himalayas with 270300 days LGP covers 78% area of the Sj Sub catchment while 22% area is under the Agro-ecological zone described as Humid/Perhumid, Lesser Himalayas with 300-330 days LGP. 5. Soil types The Sj sub catchment has heterogeneous soil with 8 different soil types. The diagram drawn below shows the distribution of different soil types in the Sj 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 A given below.
The Soil types 54 and 55 together occupy nearly 50% area of this Sub catchment. The remaining 50% area is occupied by Soil types 27, 36, 49, 57, 60 and 64 in varying proportions. 6. Table A: Soil type description
7. Soil Description 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. Shallow, excessively drained. Thermic, sandyskeletal soils on steep slopes with loamy surface, very severe erosion and strong stoniness, associated with, Rock outcrops.
Soil type unit
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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. Medium deep to deep, well drained, thermic, fineloamy soils on steep slopes with loamy surface and moderate erosion, associated with medium deep, well drained, coarse-loamy soils with loamy surface and severe erosion. 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. Medium deep, well drained, thermic, fine loamy soils on moderate slopes with loamy surface, severe erosion and slight stoniness, associated with Medium deep. Somewhat excessively drained, coarse-loamy soils with loamy surface and severe erosion. 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. Medium deep well drained thermic, coarse-Ioamv soils on moderate slopes with loamy surface and moderate erosion associated with Shallow. Excessively drained. Coarse-loamy. Calcareous soils with loamy surface and moderate erosion.
27
36
Comprehensive CAT Plan of Satluj River Basin
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54
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64