World Bosai Forum - Platform on Water and Disaster
Mapping Hydraulic and Physical Characteristics of the Indus
Basin for Early Flood Warning SystembyDr Manzoor Ahmad Malik

Pakistan Council of Research in Water Resources
November 28, 2017

Objectives and Methodology
Objectives:• To determine and map soil hydraulic characteristics of the upper Indus Basin plains.
• To record and map physical and textural profiles of the upper Indus Basin plains
Infiltration rate measurement and data analysis• Used Double Ring Infiltrometers at three step wise layers of soil at surface, 0.5 m and 1.0 m depths.
• Volume infiltrated recorded by weighing the feeding container through funnel and pipe.
• Data regressed on both cumulative and infiltration rate forms of Philips (1969) and Horton (1940) models.

PCRWR Soil Physics Laboratory Apparatus and Lab Manual
PCRWR assembled saturated soil paste extractor•Soil moisture retention•Soil texture analysis•Soil saturated extract
for chemical analysis•Infiltration rate andsaturated conductivity

Coverage Pothwar and Doabas
Potohar:

Doabas:• Geographical area = 22,254 km2• Coverage per site = 800 km2 (28 km X 28 km grid)• Sites covered: 30•••

Geographical area = 113,085 km2
Coverage per site = 1713 km2
Sites covered: : 66

Cumulative Infiltration (mm) and Incremental Infiltration Rate (mm/hr) fitted on Horton equation500
180.0070160.00

300.00

80.00
30

60.00

2040.00

1020.00

00.00
050

100150Time (min)I(t) mm, measured
Infiltration Rate Interval (mm/hr)

200200200.00150150.00

100

100.005050.00

Infiltration Rate (mm/hr)

250.000.00
50100

I(t) mm, measured
Time (min)Infiltration Rate Interval (mm/hr)

150200250I(t) mm, Horton
Infiltration Rate; Horton (mm/hr)

200.00200150.00
100.0010050.00
00.00
100150200I(t) mm, Horton

250Time (min) Infiltration Rate; Horton (mm/hr)
Infiltration Rate Interval (mm/hr)

I(t) mm, Horton
Infiltration Rate; Horton (mm/hr)

2500250.00

0 I(t) mm, measured
502500300

Infiltration (mm)100.0040

Infiltration Rate (mm/hr)

120.0050

Infiltration (mm)350.00400

140.0060

Infiltration (mm)400.00Infiltration Rate (mm/hr)

80

Representative Soil Moisture Retention of Pothwar and Doabas
v.m.c. (cm3/cm3)

CHAJ-10/M
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
1101001,000
Suction (cm)Meas. v.m.c. (cc/cc)

10,000100,000
1kPa= 10cm

Fitted. v.m.c. (cc/cc)

LBD-01/M
v.m.c. (cm3/cm3)

0.50
0.40
0.30
0.20
0.10
0.00
1101001,000
Suction (cm)Meas. v.m.c. (cc/cc)

10,000Fitted. v.m.c. (cc/cc)

100,000
1 kPa= 10cm

Mapping Soil Textural Classes
in Pothwar Region

At 1.0 m depth

At soil surface

At 0.5 m depthAt soil surface

Mapping Soil Classes in Doabas

At 1.0 m depth

At 0.5 m depthMapping Horton’s Steady State Infiltration Rate inPothwar
Percent Area of Fc Values
Fc Class≤ 15>1530

>3045

>4560

>60 90>90120>120150>150180>180210>210315

Surface

17.8313786

10---Middle

7.9

2433

141052

1

11Bottom

17.6

44

20953

110-

At 1.0 m depth

At soil surface

At 0.5 m depthMapping Horton’s Steady State Infiltration Rate inDoabas
Percent Area of Fc Values
Fc Class≤ 15>15-30>30-45>45-60>60-90>90-120 >120-300Surface

44

20118944Middle

4216981546Bottom

44211091023At 1.0 m depth

At soil surface

At 0.5 m depthMapping Organic Matter in Pothwar
Organic Matter %0.2 - 0.5
0.51 - 0.75
0.75 – 1
1.1 - 1.5
1.6 – 2
2.1 - 2.5

At soil surface

Percent of area (At Percent of area Percent of area (Atsoil surface)(At 0.5 m depth)
1.0 m depth)
191781425
19At 1.0 m depth

6141630251016162328
117
At 0.5 m depthMapping Lithology in Pothwar
Contours (ohm.m)
15 m depth

Contours (ohm.m)
5 m depth

S.
NoResistivity(Ohm-m)

Geology if
Groundwater is fresh

1<10Clay, Silt

2

11-24

3

25-39

Clayey sand, siltysand
Sand clay Silt

4> 35

Sand (fine silty)

Contours (ohm.m)
45 m depth

Contours (ohm.m)
30 m depthMapping Lithology in Doabas

Findings• Cumulative infiltration data of infiltration tests yield less scatter of data due to compensation of random error in thecumulative infiltration, whereas incremental point infiltration rates data reflects more scatter resulting in
unimpressive goodness of fit in terms of R2.
• Horton’s cumulative infiltration model persistently fits better or comparable to the Philip’s model in terms of R2 as
goodness of fit.
• Horton’s infiltration model gives direct estimate of steady state infiltration rates, which is very often required aspractical equivalent of field saturated conductivity, whereas it is difficult to acquire the same by using Philip’s model.
• Sandy loam, Loam and Silt loam are dominant soil textural classes in both Pothwar and Doabas Regions. However,spatial coverage of Sandy loam decreases with depth in the Pothwar region, whereas clay fraction decreases withdepth in the Doabas region.
• Moisture retention characteristics are more variable for similar classes of soil in the Pothwar Region than in DoabasRegion.
• Spatial coverage of infiltration rate up to 45 mm/hr is dominant in the Pothwar Region, whereas dominance of thesame is up to 30 mm/hr in Doabas Region.
• Lithological strata is more diverse in Pothwar Region as compared to Doabas where it is almost uniform.
• Soil organic matter contents in the Pothwar Region varies from 0.2 % to 2.5%. The higher percentage found in thenorthern piedmonts and the lower in the southern parts.