Soil Types – Infiltration Properties

Horton parameters

We use the Horton infiltration equation for modeling infiltration in various parts of the Scalgo Live system, including the Flash Flood Map with infiltration and drainage and Core+ DynamicFlood. Each soil type in our topsoil map can have both a "High compaction" and "Low compaction" state. The compaction state of the topsoil in a given cell is determined based on the land cover, see further below. 

The table below lists the Horton parameters for the soil types in the SCALGO Live topsoil map in their different states.

Soil type

High compaction

Low compaction

fc

f0

k

fc

f0

k

Rocks and boulders

500

1000

5

2000

5000

5

Gravel

500

1000

5

2000

5000

5

Coarse sand

30

120

5

1000

4000

5

Fine sand

25

100

5

500

2000

5

Coarse sand with clay

21

85

5

85

150

5

Fine sand with clay

20

80

5

50

130

5

Coarse clay with sand

12

50

5

30

120

5

Fine clay with sand

9

47

6

25

100

4

Clay

5

20

5

20

50

5

Fine clay

0,5

2

5

2

20

5

Very fine clay

0,01

0,1

5

0

1

5

Silt

20

80

5

50

130

5

Gyttja/peat

21

85

5

85

150

5

Bedrock

0

0

5

0

0

5

Table: Horton parameters for the generalized soil types used in SCALGO Live; infiltration rates given in mm/hr. The values were chosen based an evaluation including the following sources:

Dyhr, A. S., & Lindbæk, K. W. (2021). Sammenligning af kurvenummermetoden og Hortons model. Bachelor’s thesis, DTU.

Gregory, J.H., Dukes, M. D., Jones, P. H., & Miller, G. L. (2006). Effect of urban soil compaction on infiltration rate. Journal of Soil and Water Conservation, 61 (3) 117-124.

Kotlar, A. M., de Jong van Lier, Q., Andersen, H. E., Nørgaard, T., & Iversen, B. v. (2020). Quantification of macropore flow in Danish soils using near-saturated hydraulic properties.  Geoderma, 375. 

Parnas, F. E. Å., Abdalla, E. M. H., & Muthanna, T. M. (2021). Evaluating three commonly used infiltration methods for permeable surfaces in urban areas using the SWMM and STORM. Hydrology Research, 52(1), 160–175. 

Rossman, L. A., & Simon, M. A. (2022). Storm Water Management Model User’s Manual Version 5.2. 

Grouping into high/low compaction

The land cover type of a given location decides whether we use the high or low compaction Horton parameters for that location, the table below details how we map each land cover type to a compaction degree.

Land cover type

Compaction degree

Note

Bare land

High

Shallow vegetation

High

Dense vegetation

Low

Fields

High

Unpaved roads

High


Bare rock

N/A

All rainfall is turned to runoff, zero infiltration

Snow/ice

N/A

All rainfall is turned to runoff, zero infiltration

Table: Soil compaction degrees assigned to different land cover types.