Open Journal of Soil Science, 2012, 2, 28-32
http://dx.doi.org/10.4236/ojss.2012.21005 Published Online March 2012 (http://www.SciRP.org/journal/ojss)
Soil Erosion around Foundations of Houses in Four
Communities in Ghana
Kofi Agyarko*, Joseph Adu, Daniel Gyasi, Samuel Kumi, Lydia Mensah
College of Agriculture Education, University of Education, Winneba, Ghana.
Email: *agyarkokofi@yahoo.com
Received December 20th, 2011; revised January 23rd, 2012; accepted February 4th, 2012
ABSTRACT
Soil erosion studies around houses in four communities in Ghana were carried out from August to November, 2010.
Thirty houses were selected from each of the four communities for the study. Measurements of slope and the depth of
exposed foundatio n of houses were don e with the help of a string and a tap e measure. Data were also obtained through
questionnaire an d interview of house owners. The Pear son’s correlation coefficient was used to measure some relation-
ships among data. In the selection of site for building a house, higher percentage of the house owners considered no
factor. The major cleaning activity around the surrounding of houses was noted to be sweeping with a broom. All the
houses in the communities had their foundations exposed, 57% - 93% of the houses had exposed foundations up to a
lev el w it h in 5 1 - 10 0 cm which was classified as “Severely Exposed”. Th e e x ten t of bu i ld i ng fo un d a t io n ex p o s ed b y so il
erosion was found to be positively correlated with the age of bu ilding and th e slope of the land . Most of the respo ndents
controlled soil erosion by blocking water ways with materials such as, sand heaps, stones and sacks filled with soil.
Only 10% of the respondents from one of the communities planted grasses around their houses to control soil erosion.
Communities need to be educated to plant grasses around their houses to beautify the surroundings and to control soil
erosion.
Keywords: Soil Erosion; Foundations; Houses; Exposed
1. Introduction
Soil, a thin layer that covers most of the earth’s land sur-
face might appear insignificant relative to the bulk of the
earth, yet it is in this thin layer of soil that living king-
doms establish a dynamic relationship [1]. Soil is an im-
portant natural resource which is vital for all living or-
ganisms as major ecosystems, as well as for food produc-
tion, development and growth of settlements and popula-
tion distribution. However, this layer is gradually being
destroyed from its natural state through erosion as a re-
sult of man’s activities in searching for a better living
condition. Soil erosion causes tremendous damage to about
one-thir d of world’s cropland [2].
Global Assessment of Soil Degradation (GLASOD)
study estimated that about 15 per cent of the earth’s ice-
free land surface is afflicted by all for ms of land degrad a-
tion. Of this, accelerated soil erosion by water is respon-
sible for about 56 per cent and wind erosion is response-
ble for about 28 percent. This means that the area af-
fected by water erosion is, around 11 million square km,
and the area affected by wind erosion is around 5.5 mil-
lion square km [3].
About 80% of the World’s agricultural land suffers
moderate to severe erosion and 10% suffers slight to mo-
derate erosion. Soil erosion rates may exceed 100 ton per
ha per year in severely overgrazed pastures [4].
Effects of erosion are enormous. At the household level,
the onsite effects include damages to buildings, damages
to drains and roads, destruction of landscape, and causing
of flood. Erosion exposes building foundations which
warrant routine repair of houses. In some cases erosion
causes complete collapse of buildings and those build-
ings must be rebuilt and this adds to the expenditure of
poor households. Sometimes erosion renders households
homeless if houses collapse [5].
Some houses in older communities of Ghana are ob-
served to have their foundations dangerously exposed by
soil erosio n. The p aper attemp ts to assess th e exten t of soi l
erosion of foundation of houses and the steps taken to
solve this problem by house owners in four communities
in Ghana.
2. Materials and Methods
The study was conducted in four communities in Ghana,
*Corresponding a uthor.
Copyright © 2012 SciRes. OJSS
Soil Erosion around Foundations of Houses in Four Communities in Ghana 29
Nkrankwanta in Brong Ahafo Region, Agona and Mam-
pong in Ashanti Region and Asankragua in Western Re-
gion from August to November, 2010. Within each of the
four communities thirty houses/buildings were randomly
selected for the study. Data were obtained through the
use of questionnaire and physical measurement of per-
centage slope and the depth of the base (foundation) of
houses exposed.
The questionnaire was made up of both open ended
and close ended questions. Age of respondents, age of
houses, factors considered in selecting sites for building
houses, methods used to clean around houses and erosion
control measures taken by house owners were the major
elements of the questionnaire. The owners of the selected
houses were the respondents.
The extent of foundation of a house exposed by ero-
sion was measured from the ground level to the exposed
foundation (Figure 1) with a tape measure. Measurement
was taken at the part of the foundation where soil erosion
seemed to be very severe.
The measurement of the slope of land at the spot of a
house was done using the method described by Cowlitz
County Building Planning Department [6] (Figure 2):
Rise (H)/Run (D) × 100 = Slope in percent.
The data were analyzed using the Statistical Package
for Social Sciences (SPSS) version 11. The relationships
between the exten t of foundation exposure of houses an d
age of houses and slope of land were found using the
Pearson’s correlation coefficient at 5% significance level.
3. Results and Discussion
As the studies were conducted in the old settlements of
the communities many of the houses were found to be
more than 30 years of age (Table 1). Majority of the ow-
ners of the houses studied in the four communities were
above 45 years of age (Ta ble 2) with most of them being
males (67%, 80%, 67% and 57% for Nkrankwanta, Asan-
kragua, Mampong and Agona respectively). All the four
communities were Akan speaking societies with matri-
lineal inheritance system. Among the matrilineal Akan,
family property is inherited without subdivision, in the
first instance by the oldest surviving brother. When the
whole generation of siblings dies out, the estate then goes
to the eldest sister’s eldest son [7]. It was therefore not
surprising that most of the houses were found having
males as the house owners.
Level of Foundation
expose
d
Figure 1. Measurement of the extent of foundation exposed.
Figure 2. Measurement of slope.
Table 1. Age of houses.
Community
Nkrankwanta Asankragua Mampong Agona
Age (Years)
Number of Houses % Number of Houses % Number of Houses% Number of Houses %
Below 10 1 3 0 0 1 3 310
11 - 20 3 10 5 17 1 3 310
21 - 30 5 17 9 30 8 27 517
Above 30 21 70 16 53 20 67 1963
Total 30 100 30 100 30 100 30100
Table 2. Age of owners of surveyed houses.
Community
Nkrankwanta Asankragua Mampong Agona
Age of Respondents
(Years) Frequency % Frequency % Frequency % Frequency %
Below 25 0 0 0 0 2 7 1 3
26 - 35 6 20 2 7 5 16 5 17
36 - 45 6 20 9 30 3 10 7 23
Above 45 18 60 19 63 20 67 17 57
Total 30 100 30 100 30 100 30 100
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Soil Erosion around Foundations of Houses in Four Communities in Ghana
30
In the selection of site for building a house, higher
percentage (47%, 40%, 53% and 50% for Nkrankwanta,
Asankragua, Mampong and Agona respectively) of the
respondents considered no factor. Only few of them con-
sidered factors as, soil type and slope (Table 3). With th e
exception of those who purchased land before building a
house most of the houses especially in the old settlements
were built based on the availability of family land and
hence not much emphasis was laid on the factors consid-
ered. Consideration of factors prior to building a house is
important as these factors may have negative or positive
impact on the house and its occupants in the future [8].
The more noted cleaning activity around the houses in
the communities was sweeping (60%, 77%, 70% and 83%
for Nkrankwanta, Asankragua, Mampong and Agona res-
pectively) with a broom which was sometimes combined
with weeding (Table 4). These major cleaning activities
were seen and are still seen daily in communities in Gha-
na. Sweepings of these natures add high proportions of
sand and stones to the communities’ solid waste being
carried to refuse dump sites as ob served b y Agyarko et al.
[9]. Such removal of soil may act as precursor of soil
erosion by water around houses in the communities.
Table 5 shows the level of exposure by soil erosion of
foundations of houses in the communities. None of the
houses was found to have its foundation exposed by 10
cm or less. All the houses had their foundations exposed
to some degree. High percentage (60%, 57%, 93% and
87% for Nkrankwanta, Asankragua, Mampong and Agona
res pe cti vel y) of th e ho us es h ad thei r fo und at ion s exposed
up to a depth between 51 - 100 cm which was consider ed
as “Severely Exposed” on the bases of the classification
of the degree of exposed building foundations by the
authors (Table 6).
Table 3. Factors considered in selecting site for building a house.
Community
Nkrankwanta Asankragua Mampong Agona
Factor
Frequency % Frequency % Frequency % Frequency %
Slope 6 20 7 23 11 37 9 30
Soil type 10 33 6 20 3 10 5 17
Drainage 0 0 5 17 0 0 1 3
No factor 14 47 12 40 16 53 15 50
Total 30 100 30 100 30 100 30 100
Table 4. Methods used to clean the surr ounding of house s.
Community
Nkrankwanta Asankragua Mampong Agona
Cleaning Method
Frequency % Frequency % Frequency % Frequency %
Sweeping 18 60 23 77 21 70 25 83
Weeding 0 0 2 6 0 0 0 0
Sweeping and weeding 12 40 5 17 9 30 5 17
Others 0 0 0 0 0 0 0 0
Total 30 100 30 100 30 100 30 100
Table 5. Depth of foundation of houses exposed.
Community
Nkrankwanta Asankragua Mampong Agona
Depth
Exposed (cm) Number of Houses % Number of Houses% Number o f Houses% Number of Houses %
Classification of
exposed depth
Below 10 0 0.00 0 0.000 0.000 0.00 Unexposed
10 - 30 2 6.67 2 6.670 0.000 0.00 Exposed
31 - 50 7 23.33 5 16.662 6.672 6.67 Highly Exposed
51 - 100 18 60.00 17 56.6728 93.3326 86.66 Severely Exposed
Above 100 3 10.00 6 20.000 0.002 6.67 Extremely Exposed
Total 30 100 30 100 30 100 30 100
Copyright © 2012 SciRes. OJSS
Soil Erosion around Foundations of Houses in Four Communities in Ghana 31
Table 6. Classification of foundation exposure.
Depth Exposed (cm) Classification
10 Unexposed
10 - 30 Exposed
31 - 50 Highly Exposed
51 - 100 Severely Exposed
100 Extremely Exposed
Most houses in the Mampong and Agona communi-
ties were found on the slope between 5% and 9%, most
of the houses in the other communities were found on
the slope between 1% and 5% (Table 7). Though foun-
dation of houses may be exposed by soil erosion with
time if proper measures are not put in place, the slope of
the land is a major factor to be given a critical con sidera-
tion. The slope therefore could have attributed to the
percentage differen ces of the nu mber of houses with th eir
foundations considered “Severely Exposed” among the
communities—93% and 87% for Mampong and Agona
communities respectively and 60% and 57% for Nkrank-
wanta and Asankragua communities respectively (Table
5).
The extent of building foundation exposed by erosion
was found to be positively correlated with the age of build-
ing and the slope of the land (Table 8).The slope had a
higher positive co rrelation figu re than the age of th e build-
ing. Slope is considered to be a critical factor in deter-
mining soil erosion and fields with slopes of 10 - 15 per-
cent slopes will likely be very prone to erosion [10].
Though, almost all the houses in the communities were
built on land slopes of less than 9%, and may be consid-
ered less prone to soil erosion, the length of the slope
which is also another critical factor in determining soil
erosion could cause even a constant slope of 2 percent to
erode severely [10].
Measures taken to control soil erosion around houses
in the communities therefore are imperative to prevent
collapse of houses which may lead to death of human be-
ings. Apart from the respondents in Mampong where
only 27% control soil erosion in their community more
than half (53%, 60% and 67% for Nkrankwan ta, Asank-
ragua and Agona respectively) of the respondents in the
other communities control soil erosion (Table 9 ). Table
10 shows the various soil erosion control measures em-
barked by the communities. From the table it is observed
that more than half (75%, 61%, 75% and 50% for
Nkrankwanta, Asankragua, Mampong and Agona re-
spectively) of the respondents controlled soil erosion by
blocking water ways with materials such as, sand heaps,
stones and sacks filled with soil. Few of the respondents
redirected the flow of running water. Though planting of
grasses has been found to be effective in soil erosion
control, only 10% of the respondents from Agona com-
munity planted grasses around their houses to control soil
erosion, the rest of the communities did not embark on
this control measure and even weeded any kind of vege-
tation around their houses.
Table 7. Percentage slope.
Community
Nkrankwanta Asankragua Mampong Agona
Slope (%)
Number of Houses % Number of Houses% Number of Houses % Number of Houses%
Below 1 0 0 0 0 0 0 0 0
1 - 3 20 67 18 60 1 3 0 0
3 - 5 10 33 7 23 2 7 1 3
5 - 7 0 0 5 16 10 33 11 37
7 - 9 0 0 0 0 11 37 14 47
Above 9 0 0 0 0 6 20 4 13
Total 30 100 30 100 30 100 30 100
Table 8. Correlation between the extent of foundation exposure of houses and age of houses and slope of land.
Community
Nkrankwanta Asankragua Mampong Agona
Factor Age of buildingSlope of landAge of buildingSlope of landAge of buildingSlope of landAge of buildingSlope of land
Extent of foundation
exposure 0.2690.7030.2440.8080.4790.9470.1480.555
Copyright © 2012 SciRes. OJSS
Soil Erosion around Foundations of Houses in Four Communities in Ghana
32
Table 9. Responses to the control of soil erosion.
Community
Nkrankwanta Asankragua Mampong Agona
Response to erosioncontrol
Frequency % Frequency % Frequency % Frequency %
Control erosion 16 53 18 60 8 27 20 67
Do not control erosion 14 47 12 40 22 73 10 33
Total 30 100 30 100 30 100 30 100
Table 10. Erosion control measures.
Community
Nkrankwanta Asankragua Mampong Agona
Erosion control measure
Frequency % Frequency% Frequency% Frequency %
Redirection of water wa ys 4 25 7 39 2 25 8 40
Block water ways 12 75 11 61 75 10 50
Planting grasses 0 0 0 0 0 0 2 10
Total 16 100 18 100 8 100 20 100
4. Conclusions and Recommendations
All the houses in the communities had their foundations
exposed, with higher number of them being severely ex-
posed. Efforts were made by the communities to control
soil erosion around their houses through blocking of wa-
ter ways with materials such as, sand heaps, stones and
sacks filled with soil, however, plantin g of grasses in the
surrounding of houses was almost absent, surrounding of
houses were seen bare without any kind of vegetation.
Communities should be encouraged to plant grasses aro-
und their houses to b eautify the surround ings and to con-
trol soil erosion.
Alternative cleaning methods around the houses should
be considered in the communities as the sweeping and
weeding methods adopted by the communities carry soil
away and induce soil erosion.
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Copyright © 2012 SciRes. OJSS