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Water harvesting from roads in Tigray, Northern Ethiopia:

Practices, Opportunities and Design Considerations

By:

Kifle Woldearegay1, Diego Garcia-Landarte Puertas2, Frank Van

Steenbergen2, Martin Van Beusekom2, Marta Agujetas2

(1Mekelle University, Ethiopia; 2MetaMeta, The Netherlands)

May 2014

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1. Introduction

Ethiopia in general and the arid to semi-arid environments of the country in particular has

been associated with food insecurity which in turn is related to water insecurity. One of the

un-recognized potentials which need due consideration in Ethiopia and in many Sub-Saharan

Africa is water harvesting from roads.

A well planned and implemented road development has a number of benefits among which is

fueling growth process through different activities of the development endeavors of a nation

including: creating market access opportunities for agricultural products, access to services

(health, schools, etc) and contribute to the socio-economic development of an area.

Understanding the importance of the sector, Ethiopia has been involved in massive road

construction in the last two decades. The country plans to undertake further road development

in order to connect local administration regions (Tabias/Kebele).

In the case of Tigray region, for example, Until the year 2015, the Tigray region, for example

plans to construct a total of 5177Km new roads in which 1004km from Regional budget and

4173km from Federal budget. Moreover, the region plans to construct 3086 km all weather

roads to improve the existing 230 kebelle network to 712 in 2014/15. This is expected to

decrease the existing distances to reach the all weather roads from its 6.223 km to 2.36 by the

end of 2014/15.

Despite the benefits created from road development, road construction can create a number of

problems especially to communities close to the roads. Some of the major problems include:

flooding, water logging, erosion and the development of gullys, and other environmental

problems.

This study, which is part of the UPGro Catalyst research grant, has tried to assess the effects

of water from roads, and the status as well as opportunities for water harvesting from roads in

Tigray, Northern Ethiopia. The site selected in this study is the “Freweign-Hawzien-Abreha

Weatsbeha-Wukro route” in Tigray, Northern Ethiopia.

2. Objectives of the study

The main objectives of the study were to:

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§ Undertake a detailed inventory of the effects of water from roads in the study area.

§ Evaluate the geohydrological and geotechnical condition of the area in relation to

suitability for water harvesting.

§ Assess the practice of water harvesting from roads in Tigray, with more focus to the

practice in the Freweign-Hawzien-Abreha Weatsbeha-Wukro route.

§ Review the current approach and institutional arrangement in relation to the design

and construction of roads, water resources development, and natural resources

management.

§ Recommend approaches for the design and construction of multi-functional roads that

integrate water harvesting in the study area and in other parts of Ethiopia.

3. Research Approach/Method

The following research approaches were used:

§ Review of previous studies: previous studies on geology, geohydrology, land use/land

cover, erosion processes, and geotechnical issues from consultancy reports, published

research papers, technical notes, and design reports were reviewed.

§ Review of design manuals: review was made on the hydrological design approach of

roads and on the environmental impact assessment manual of ERA. Moreover,

assessment was made on the linkages between road development, water resources

development/management, natural resources and environmental issues, and

community involvement in the design, construction and maintenance of roads.

§ Collection of existing data: existing data on population, land use/land cover, soils,

settlement, and roads were gathered.

§ Collection of data on rainfall and hydrology: data related to rainfall and hydrology

was collected for limited meteorological stations in the study areas.

§ Generation of hill shade of the areas was made from SRTM-DEM (20 m resolution).

§ Inventory of areas affected by water from roads: this included detailed survey of

drainage systems (culverts, bridges) and areas affected by gully erosion, flooding, and

water logging along the routes. Moreover, locations of water points mainly shallow

wells along 5Km radius of the road is inventoried.

§ Evaluation of the geohydrological condition of the route: detailed field evaluation of

the rocks and soils along the 5Km radius of the road was made including the rock/soil

types and their hydraulic properties.

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§ Characterization of erosion sites: for each of the gully sites visited during the field

work, assessment was made for several factors such as: (a) size (length, width, depth)

of gully erosion sites, (b) physical properties of the soils, (c) underlying bedrock

types, (d) hydrological condition (surface and subsurface water flow indicators) of the

site, (e) vegetation cover, (f) association of erosion sites with infrastructures (roads,

drainage systems, water reservoirs, etc), (g) previous efforts made to address erosion

problems, (h) effects of gully erosion, and (i) general catchment characteristics of the

erosion sites.

§ Soil sampling and laboratory testing: six soil samples were collected from a

representative gully erosion site in order to evaluate the effects of gully erosion from a

culvert on in-situ moisture of soils. Samples were collected along a transect

perpendicular to the gully length and the in-situ moisture contents of the soils were

measured in the laboratory.

§ Water sampling and laboratory testing: in order to assess the carbon content of the

water four surface water samples were collected from a water logged area close to the

road. Two groundwater samples were also collected to evaluate the water quality of

the wells close to the roads.

§ In-situ permeability tests: in order to estimate the in-situ permeability of the soils,

inverse auger hole test method was applied in the field at five different locations along

the route (with three tests in each site).

§ Data collection through focused group discussions: during the field visit to the

different regions, discussions were held with communities and local government

representatives.

§ Data analysis and interpretation: this involved evaluation of: (a) the effects of water

from roads, (b) the geohydrological suitability of the areas for water harvesting from

roads, (c) the practices of water harvesting from roads and the potentials for future

implementation, and (d) water quality aspects of water from roads.

§ Recommendations: approaches to be considered for the design and construction of

multi-functional roads which takes into consideration water harvesting from roads.

4. Study area

4.1 Location

The detailed survey was made for the route: Freweign-Hawzien-Abreha Weatsbeha-Wukro

routes in Tigray, Northern Ethiopia. The road crosses three woredas: (a) Saesie Tsaeda Emba

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(woreda center is Freweign town), (b) Hawzien woreda (woreda center is Hawzien town),

and (c) Klite Awlaelo woreda (woreda center is Wukro town) (Figure 1). The surveyed routes

include both feeder roads and asphalt: Freweign-Megab route is asphalt, and Megab-Abreha

Weatsbeha-Wukro route is all weather gravel road. The Wukro-Freweign route is a highway

asphalt road and is not considered in this survey.

Figure 1: Location map of the Freweign-Hawzien-Abreha Weatsbeha-Wukro route, Tigray,

Northern Ethiopia.

4.2 Population and livelihood

Population: A total of 49,574 household heads and an estimated total population of 236,486

of which 51.7% are female and 48.3% male live in these woredas. From the total population

of the woredas, about 76.4% live in rural areas. From the total rural dwellers, 63.4% are

female while male accounts about 36.6%. The average family size per household in the study

area is about 5 persons.

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Livelihood of the communities: The communities in the watersheds have been food insecure

for a number of reasons, among which are: (a) land degradation mainly erosion and reduction

in soil fertility, (b) due to short rainy season coupled with high rainfall variability between

seasons, (c) the small land size that rarely exceeds 0.5 ha per family and (d) absence of

irrigation practices.

The dominant mode of livelihood of the population is mixed crop and livestock agriculture.

The predominant agricultural practice in the study area is traditional crop-livestock mixed

farming. The major rainfed crops grown is dominated by cereals and legumes such as Barely,

Wheat, Beans, Vetch, Peas, Faba Beans, Lentils, Teff, Maize while the irrigated crops include

Maize, Tomato, Onion, Pepper, Carrot, Cabbage and fruit trees. Other income sources

include quarrying (stone gathering), wages, pity trade, etc. In general, livelihood

diversification of the study area increases with market proximity.

Rainfed-agriculture: The total cultivated land in the area in 2009/2010 production year was

34,911.1 hectare while the corresponding total yield was 793,540.2 quintal. It was found out

that, with an average of 13.1 quintal/ha, the average annual yield varied from 7.9 quintal/ha

to 22.7 quintal/ha. The major factor contributing to the variability is the unreliability of

rainfall both in amount and distribution. The other factors causing low productivity include

poor soil fertility, poor agricultural inputs including improved seeds and fertilizer, poor

tillage practices and weed problems. As a result, farmers do not produce sufficient food and

are exposed to year round food aid.

The population of the study area which is similar to the other parts of the country grows by

2.5% which requires parallel growth in the agricultural commodity sector. However,

recurrent drought and low yields have caused the growth rate of food production to lag

behind the rate of population growth.

Irrigated agriculture: Various water harvesting technologies ranging from individual farm

household to community level are used in the study area for irrigation. Some of these include

hand-dug wells, ponds (Horoye), river diversions and earth dams. The total irrigated land in

the area in the year 2013 was estimated to be about 1800 hactar (TBoARD, 2013).

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4.3 Topography and climate

The landscape of the project area is associated with wide ranges of landforms which include

plateaus, mountains, rolling hills, steep hill slopes and deeply incised valleys. The slope

gradients range from flat plains to over 40%. The slope range renders itself very conveniently

to both on-farm and off-farm water harvesting practices.

The catchment encompasses a wide range of altitude starting from 1,500 to 3,300 m.a.s.l with

diverse rock types (e.g., sedimentary, metamorphic and igneous origin) and various cover

types and land use. The mean annual rainfall and temperature of the area varies from 552 mm

– 767 mm, and 16 – 20° C respectively.

The climate of the project area is classified as semi-arid, with erratic and torrential rainfall

that often lasts for not more than 3 months (end of June to beginning of September). Actual

and potential evapotranspiration are about 540 mm and 1,390 mm respectively.

5. Geohydrology and groundwater potential

5.1 Geohydrology of the route

The geohydrology of Tigray region is highly variable depending on a number of parameters,

in particular: (a) rock/soil types and their hydraulic properties, (b) terrain conditions (slope

angle and shape), (c) land cover and soil/water conservation measures at upper watersheds,

and (d) size of the recharge area vis-à-vis the receiving area.

Though the northern Ethiopia is characterized by various rock and soil types, the study area is

mainly dominated by the following rock and soil types: (a) Metamorphic rocks, (b) Paleozoic

sediments (Tillites/post-glacial sediments, and Enticho Sandstone), (c) Mesozoic sediments

which include Adigrat sandstone, Antalo limestone and shale, and (d) Unconsolidated

deposits (mainly residual soils and alluvial types). The geohydrological characteristics of

these rocks and soils is summarized as follows:

5.1.1 Metamorphic rocks:

According to various authors (e.g. Mohr 1983; Tadesse et al. 2003) the metamorphic rocks in

the area include metasediments and metavolcanics. These rocks are exposed in limited areas

(along deep rivers) in the area. The metasediments are generally classified as rocks with low

permeability and poor aquifer characteristics. In many cases, however, these metasediments

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have moderate aquifer characteristics, as a result of weathering, at very shallow depths (not

exceeding 10 meters). Fractured metavolcanic rocks have relatively higher permeability at

shallow depths (in most cases not exceeding 50meter deep). With increase in depth the

degree of fracturing and hence the permeability tends to reduce unless it is affected by major

fault systems. Metavolcanic rocks are, therefore, classified as rocks with moderate aquifer

characteristics for groundwater development. Due to this, many of the valley floors underlain

by metamorphic rocks are among the areas with extensive shallow groundwater development

in the area.

5.1.2 Paleozoic sediments:

These rocks include Enticho sandstone, and glacial tillites(Mohr, 1962, 1967, 1983; Kazmin,

1972).

5.1.2.1 Enticho Sandstone

The majority of the route is dominated by Enticho sandstone. These rocks are fine to medium

grained, slightly to moderately weathered, horizontally bedded, jointed sandstone with sand-

silt matrix and poorly sorted pebbles and boulders. When weathered (mostly not exceeding

15m as observed from existing hand-dug wells), the Enticho sandstone has moderate to high

permeability. With increase in depth, the permeability tends to decrease. Among the

productive shallow wells in the areas are the valley floors underlain by Enticho sandstones

along the route.

5.1.2.2 Glacial Tillites

These rocks are exposed only in limited areas along the route. Glacial Tillites have generally

low permeability due to the sand-silt-clay matrix in these rocks. In some cases they are

interbedded with thin layers of silty limestone, and with poorly sorted pebbles and boulders.

At shallow depth (not exceeding 5m depth), however, these formations have moderate

permeability due to weathering.

5.1.3 Mesozoic sediments

Mesozoic sediments: these rocks were studied by various authors (e.g. Assefa, 1981, 1991;

Russo et al., 1999). From the Mesozoic rocks, those exposed along the route or adjacent to

the route include: Adigrat sandstone, and Antalo group (limestone, shale):

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5.1.3.1 Adigrat Sandstone

Though these rocks were not encountered along the road, they are exposed close to the

routes. These Adigrat Sandstones are characterized by high degree of fracturing. The

geomorphological expression of these rocks (ridge forming) dictates their suitability as

recharge zones to the valley floors. These rocks are categorized as poor aquifers for

groundwater development.

5.1.3.2 Antalo limestone

Antalo limestone is exposed along the Abreha Weatsbeha-Wukro route. These rocks are hard

limestone and shale intercalations. As a unit, it is classified as a rock with moderate aquifer

characteristics. In many places, cold springs emerge at the contact of the limestone beds with

the intercalating shales and marls.

5.1.3.3 Agula Shale

Agula shale is exposed only in limited areas. This formation is characterized by shale, marl

and claystone which is intercalated with fine crystalline black limestone. Generally, this unit

is having poor aquifer characteristics. Due to the weathering of these rocks at shallow depth,

however, they contain shallow groundwater.

5.1.4 Unconsolidated deposits

These include alluvial and residual deposits. The permeability and productivity varies from

place to place depending on grain size, sorting and thickness. The thickness of these

sediments is limited in the area; mostly not exceeding 10 meter.

The silty sand soils are the most dominant ones along the whole route and results of inverse

auger hole test in these soils revealed that these soils have permeability which range from

2.5*10-2 cm/sec to 3.4*10-3cm/sec. Most of the unconsolidated sediments along the route are

categorized as good aquifers for shallow groundwater development. This is confirmed by the

extensive shallow groundwater development in the plains of the study area.

5.1.5 Geological structures

Different types of geological structures characterize the study area. Many water supply wells

have been developed in fractured aquifers in the area and in other parts of Tigray.

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5.2 Groundwater development

In the three woredas (Saesi Taseda Emba, Hawzien and Klite Awalelo), the flat plains and

valley floors are associated with shallow groundwater development for water supply and

irrigation purposes (Figure 2a, b). In recent years, small-scale irrigation using shallow

groundwater is practiced, especially since the year 2000. In these three woredas, over 3000

hand-dug wells have been developed for irrigation use in the years 2011-2013 alone.

Assessment/inventory of representative hand-dug wells show variable depth of water table.

At the end of rainy season, the water table varied from zero to about 1m below the ground

surface. In the dry season, however, the measured water level varied from dry to 5m depth.

Food security is strongly associated with water security and hence irrigation development in

the area.

Groundwater is the main source of water for domestic use in the area. In the last five years,

however, shallow groundwater is commonly used for small-scale irrigation in the area. As a

result, out of the total 1800hectar irrigated land in the year 2013, a total of 550hectar of land

was irrigated using shallow groundwater systems. The maximum land size that a single

farmer is able to irrigate so far (using shallow groundwater as well as other sources) in the

area is 30% of the cultivable land. The reason for not able to irrigate more land is related to

shortage of water.

Though not strongly linked and coordinated with water harvesting from roads, natural

resources management efforts which include construction of deep-trenches and percolation

ponds as well as biological measures (afforestation) and area closures are implemented in the

area.

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Figure 2a: A hand-dug well developed in areas underlain by Enticho Sandstone along the

Freweign-Hawzien road (close to the road), Tigray, Northern Ethiopia. The well is used for

small-scale irrigation.

Figure 2b: A hand-dug well developed in areas underlain by Enticho Sandstone along the

Megab-Abreha Weatsbeha road, Tigray, Northern Ethiopia. The well is used for small-scale

irrigation.

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Figure 2c: Hand-dug wells developed in areas underlain by Glacial Tillites/post-glacial

sediments in Klite Awlaelo woreda, Tigray, Northern Ethiopia.

6. Effects of water from roads

In order to evaluate the effects of water from roads, detailed survey was done for the route:

Freweign-Hawzien-Megab-Abreha Weatsbeha-Wukro road, Tigray, Northern Ethiopia. The

Freweign-Hawzien-Megab route is asphalt, while the route Megab-Abreha Weatsbeha-

Wukro road is a gravel road. The survey involved detailed assessment and documentation of:

(a) locations of Culverts, Irish bridges, and Bridges, (b) areas affected by gully erosion, (c)

sites affected by water logging and flooding, and (d) sites where efforts have been made to

implement different soil and water conservation measures along the 5Km radius from the

main route. Results of the study is given in the following sections.

6.1 Locations of culverts and bridges

A total of 118 culverts (110 pipe culverts and 8 box culverts), 4 Irish bridges, and 8 bridges

have been inventoried along the route (Figure 1). The pipe culverts have variable capacity

that range from single pipe to triple ones.

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6.2 Negative effects of water from roads

Detailed inventory and assessment of the effects of water from roads was carried out in the

period July to September 2013. Results show that water from roads have caused a number of

problems which include: (a) erosion (downstream areas and road sides), (b)

siltation/sedimentation of downstream, upstream, and side drainage areas, (c) water logging

(upstream and downstream areas), and (d) damage on dwelling houses and on water

harvesting systems (groundwater wells and ponds).

6.2.1 Erosion problems

From the total of 118 culverts, gully erosion was recorded at downstream of 68 culvert

locations (Figure 3a, b, c, d). The size of the gullys were found to be variable: depth range

from about 1m to 4.5m, width vary from 1.5m to 5m, and length range from 10m to over

500m. In 35 locations, road side erosion was recorded (Figure 3e). Expansion of gullys and

creation of new ones is not uncommon. In all the erosion affected sites, gullys have

terminated after reaching the bedrock. No major gully erosion problem was noted at Irish

bridge locations. Moreover, since most of the bridges were constructed on a hard rock, no

active erosion was recorded on the major bridge sites along the route.

Figure 3a: Erosion at upstream side of a culvert in Freweign area, Tigray, Northern

Ethiopia.

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Figure 3b: Erosion at downstream side of a culvert in Freweign area, Tigray, Northern

Ethiopia.

Figure 3c: Downstream gully erosion due to water from a culvert in Freweign area, Tigray,

Northern Ethiopia.

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Figure 3d: Downstream gully erosion due to water from a culvert in Abreha Weatsbeha area,

Tigray, Northern Ethiopia.

Figure 3e: Example of a site affected by erosion (from road side drainage) in Freweign area,

Tigray, Northern Ethiopia. The trench (which used to be a farmland) was excavated to

channel the road side runoff to downstream grazing land.

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In order to evaluate the in-situ moisture distribution across a gully site, soil samples were

collected from field and analyzed in the laboratory. Results of the analysis (Table 1) show

that the in-situ moisture content of the soil increases with increase in distance from the gully.

Close to the gully the moisture content was found not to be more than 8% but at 10m away

from the gully the moisture content reached upto 45%.

Sample Cod Distance from gully (m) Moisture content (%) Soil type

LS01 1 5 Silty sand

LS02 5 18 Silty sand

LS03 10 38 Silty sand

RS01 1 8 Silty sand

RS02 5 26 Silty sand

RS03 10 45 Silty sand

Table 1: Moisture distribution across a gully (LS= Left Side; RS= Right Side) in Freweign

area, Tigray, Northern Ethiopia. Note that the depth of sampling was 0.5m and the soil type

in the site is silty sand type. Samples were collected one day after a 50mm rainfall in the

area.

The results of the laboratory test was in line with the moisture content of the crops; crops

close to the gully have shown early maturation due to less moisture content in the soil (Figure

4).

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Figure 4: Downstream view of a gully created with water from a culvert in Freweign area,

Tigray, Northern Ethiopia. The moisture content and the productivity of land was found to

reduce with decrease in distance from the gully.

6.2.2 Siltation/sedimentation problems

At 15 culvert locations and 5 road sides, sedimentation problems were recorded. As a result,

farmlands have been affected. In some areas, such negative effects are becoming

opportunities for sand mining (Figure 5).

Figure 5a: Damaged crops due to siltation/sedimentation problems with water from a culvert

in Freweign area, Tigray, Northern Ethiopia.

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Figure 5b: A sinkhole (15m wide and 8m deep) created due surface and subsurface erosion

with water from a culvert in Freweign area, Tigray, Northern Ethiopia.

6.2.3 Water logging

Water logging issues were documented at 37 locations along the road alignment (Figure 6a,

b). The water logged areas include farm lands, and grazing lands. The causes for water

loggings, as observed from the field, were the following (Figures 6c, d, e): (a) inlet level of

the culvert being higher than the upstream ground level, (b) outlet level of the culvert being

lower than the downstream ground level, (c) reduction in pipe diameter due to

siltation/sedimentation problems, and (d) absence of drainage systems and/or improper

locations of drainage systems as some of the culverts could have been located in .

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Figure 6a: Water logging at upstream side of a road along the Freweign-Hawzien route in

Tigray, Northern Ethiopia.

Figure 6b: Water logging behind an embankment road along the Frewign-Hawzien road,

Northern Ethiopia

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Figure 6c: Outlet level of the culvert is lower than the downstream ground level, leading to

ponding of water at upstream of the culvert in Freweign-Hawzien route, Tigray, Northern

Ethiopia.

Figure 6d: Siltation is causing reduction in the size capacity of the pipe culvert leading to

water logging problems along the Frewign-Hawzien route, Tigray, Northern Ethiopia.

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Figure 6e: Siltation is causing reduction in pipe size leading to water logging in Debre Tsion

area (along the Hawzien-Abreha Weatsbeha), Tigray, Northern Ethiopia.

6.2.4 Flooding

In 34 locations, water from culverts and road side drains have caused flooding of farmlands,

ponds, and shallow hand-dug wells. The most damaging flooding with water from culverts

and road side drainage were recorded on 18 locations along the route (e.g. Figure 7a, b). It

has caused: (a) damage to 8 dwelling houses, (b) silting-up of 4 ponds and 5 shallow

groundwater wells, (c) increase in the size and depth of previously exiting gullys, and (d)

damage to farmlands and crops.

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Figure 7a: Flood from road side drainage has caused damage on dwelling houses and on a

pond along the Freweign-Hawzien route in Tigray, Northern Ethiopia.

Figure 7b: Dwelling houses damaged due to flood from culvert in Freweign area, Tigray,

Northern Ethiopia.

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6.3 Positive effects of water from roads

Though it was not planned, a number of positive effects of water from roads were noted

during the survey which include: (a) upstream and downstream water logging, recharging

shallow groundwater wells. In ten locations, water from roads is recharging water supply and

irrigation wells in the area (e.g. Figure 8). Though not along the Freweign-Hawzien-Abreha

Weatsbeha-Wukro road, runoff from bridge is channeled into series of deep trenches to

enhance shallow groundwater wells in Tigray (Figure 9a). Road development could also have

a positive and negative impact where by upstream wells could be enhanced and downstream

ones depleted, as noted along the Hawzien-Megab road in Tigray, Northern Ethiopia (Figure

6b).

Another benefit of water from roads is deposition of sand at road sides and upstream areas of

Irish bridges. In 13 different locations along the route, sand mining activity is practiced by

young entrepreneurs (e.g. Figure 10). The sand mined along the roads was found to be either

a road side deposit or a deposit at upstream of Irish bridges. If properly managed, such

practice is believed to keep the safety of roads and at the same time give economic benefits to

local communities.

Figure 8: Upstream water logging is enhancing groundwater recharge of a well along the

Hawzien-Megab road, Tigray, Northern Ethiopia.

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Figure 9a: Water from a bridge is channeled into series of deep trenches which are acting as

recharge to shallow groundwater system in Negash area, Tigray, Northern Ethiopia. Shallow

groundwater in the area is used for water supply and irrigation purposes. A shallow well

which was dry in the year 2005 is now used for small-scale irrigation.

Figure 9b: Typical example of effects of road construction on shallow groundwater along the

Hawzien-Megab road, Tigray, Northern Ethiopia. In the upstream side of the road shallow

wells are developed for irrigation use. In the downstream side wells were excavated but the

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yield was not enough to use it for irrigation purpose. Before the road upgrading the situation

was the reverse: there was more water at downstream side than at upstream side.

Figure 10: Sand mining practice along the road side in Wukro area, Tigray, Northern

Ethiopia.

7. Practices of water harvesting from roads

So far there is no systematic approach to water harvesting from roads. Most of the practice of

water harvesting introduced in northern Ethiopia is a coincidence as it was not designed for

the purpose.

7.1 Water harvesting from roads in the study areas

The Tigray Bureau Agriculture and Rural Development (TBoARD) has been involved in a

number of activities related to natural sources management efforts in the region. So far there

does not exist any integration between road construction and natural resources

management/water harvesting.

Comprehensive assessment was made on the practices of water harvesting from roads along

the study areas. The main practices implemented so far were financed by the government

(particularly the TBoARD) and include: (a) use of ponds to collect road side drainage, (b)

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channeling water from culverts and road side drainage into series of deep trenches, and (c)

shallow groundwater development upstream of Irish bridges.

7.1.1 Use of ponds to harvest water from roads

Since the year 2010, the TBoARD in collaboration with communities and NGO’s has been

trying to construct different soil/moisture retention structures. One of these techniques is

construction of ponds to collect water from any source including road side drainages (Figure

11). These structures are used for surface water storage and groundwater recharge. From the

whole route only 5 ponds have been constructed by the government and 3 ponds by local

communities (privately).

Figure 11: A 3m deep and 8m wide pond (Horeye) used to collect road side drainage from

roads along the Freweign-Hawzien route, Tigray, Northern Ethiopia.

7.1.2 Channeling water from culverts and road sides into deep trenches

In only 7 locations, water from culverts and road side drainages was channeled into deep

trenches (Figure 12a, b). In other parts of Tigray, for example in Abyi Adi area, water from a

culvert is channeled into a pond (Figure 12c, d). In rare cases, for example in Agbe area,

Tigray, water from a bridge is diverted into irrigation field (Figure 12e).

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Figure 12a: Runoff from culverts being channelled to deep trenches in Hawzien area, Tigray,

Northern Ethiopia (Photo by Kifle Woldearegay and Mohammed Abdelkadir, July 24, 2013).

Figure 12b: Water from culverts is channeled into series of deep trenches to reduce erosion

at downstream areas and enhance the groundwater system along the Hawzien-Megab area,

Tigray, Northern Ethiopia.

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Figure 12c: Water from culverts is channeled into a pond in Abyi Adi area, Tigray, Northern

Ethiopia.

Figure 12d: Pond (45m long, 30m wide and 7m deep) in which water from culverts is

channeled into in Abyi Adi area, Tigray, Northern Ethiopia. Pond mentioned in Figure 12c.

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Figure 12e: Water from a bridge is diverted into an irrigation field in Agbe area, Tigray,

Northern Ethiopia.

7.1.3 Shallow groundwater development upstream of Irish bridges

Along the Freweign-Hawzien-Abreha Weatsbeha-wukro route, four Irish bridges were

identified. A hand-dug well is developed at upstream of Irish bridge in one site (Figure 13).

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Figure 13: A hand-dug well is developed at upstream of an Irish bridge along the Hawzien-

Abreha Weatsbeha route in Tigray, Northern Ethiopia.

7.2 Practice of water harvesting from roads in other areas of Tigray

In addition to the practices of water harvesting from roads indicated above, the following

additional techniques have been documented applied to harvest water from roads in Tigray

but outside of the Freweign-Hawzien-Abreha Weatsbeha-Wukro route:

7.2.1 Spring capture from roads

Though not commonly used, spring capture from road cuts is practiced in Tigray, mainly for

water supply purposes (e.g. Figure 14).

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Figure 14: Spring developed from a road cut which is now used for rural water supply in

Megulat area, Tigray, Northern Ethiopia.

7.2.2 Use of borrow pit

The use of borrow pits as surface water storage and groundwater recharge is an option of

water harvesting from roads which was not considered until recently in Tigray. As part of the

contract agreement between a contractor and client, borrow pits are often expected to be

filled and given back to land owners. It is often the case that even if the land is filled-back, it

can not be productive as what it used to be.

In recent years, because communities are becoming aware of the importance of water, borrow

pits are being used as surface storages and groundwater recharge in limited areas of Tigray

(e.g. Figure 15a, b). In some sites the borrow pits are close to a terrains where seepage water

comes from the hillslopes. In the case of borrow pit in Axum area seepage water from the

road sides and the hillslopes is contributing to the base-flow to: the borrow pit which is

currently used for swimming, livestock, groundwater recharge and irrigation.

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Figure 15a: A borrow pit (250m long, 80m wide and 15m seep) which is currently used for

irrigation development in Axum area, Tigray, Northern Ethiopia.

Figure 15b: A borrow pit (400m wide, 650 long, and 10m deep) which is yet to be used for

irrigation in Sheraro area, Tigray, Northern Ethiopia.

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The borrow pit in Sheraro area was developed using blasting and has left rocky reservoir

floors. The borrow pit is used for swimming, washing and small-scale irrigation. Until mid

2014, 5 people are reported to have been drowned in the pit; causing a serious concern by the

communities. The local and regional government are planning to change the site into proper

water harvesting after getting advice from the UPgro catalysis grant holders. The pond is

recharged from the surrounding stream as the level of water in the pond is lower than the

stream level.

7.2.3 Shallow groundwater upstream and downstream of roads

In different parts of Tigray, a numbers of scenarios were noted in relation to road

construction and downstream-upstream groundwater conditions. In some areas, for example

in Edaga Hamus area (Figure 16a), road upgrading has increased the upstream groundwater

storage which later on was turned into a pond by excavating the sand aquifer. Now this water

is used for irrigation and livestock.

Figure 16a: Upgrading of the road has resulted in an increase in the groundwater storage at

upstream of the road in Edaga Hamus area, Tigray, Northern Ethiopia.

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In other areas, after upgrading of a road the embankment was raised to about 2m above

original ground level and this lead to creation of water logged areas at upstream of the road.

This effect has improved both the upstream and downstream groundwater wells, for example,

in Shire area, Tigray, Northern Ethiopia (Figure 16b).

The other scenario noted from the survey in different parts of Tigray, for example in Shire

(Figure 16c) and Negash (Figure 16d) areas, is that due to road upgrading, shallow wells at

upstream of the roads which used to dry fast have improved their yield. This is attributed to

the reduction in permeability of the soils at the road foundation due to compaction.

Figure 16b: Upgrading of the road has resulted in an increase in the groundwater recharge

for both downstream and upstream areas of the road in Shire area, Tigray, Northern

Ethiopia.

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Figure 16c: Upgrading of the road has enhanced the groundwater yield in Shire area,

Tigray, Northern Ethiopia.

Figure 16d: Upgrading of the road has enhanced the groundwater yield in Negash area,

Tigray, Northern Ethiopia. Before the upgrading of the road, the well used to be dry.

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8. Current road design approach and stakeholder involvement

8.1 Current road design approach

In Ethiopia, the road sector is generally considered as well organized and equipped with

standard design manuals and guidelines. The Ethiopian Roads Authority has developed

design manuals for the different components of a road. Since issues of road and water is more

related to geotechnical, hydrological and environmental aspects, review was made on the

existing road design manual (specifically the drainage design manual of ERA - 200):

From the review, the following points are noted:

§ According to the ERA manual, drainage systems are designed to: (a) to prevent road

damage during the most usual floods, and (b) to minimize the modifications in the

hydrology of the area.

§ No design consideration is given to water harvesting except for certain detention

structures in which the objective is not to harvest the water but to reduce the peak

discharge and only detain runoff for some short period of time.

§ No design consideration is given to any possibility of developing groundwater

recharge systems.

As indicated in section 7 of this report, different water harvesting practices have been

implemented in Tigray region. These practices were mainly introduced by the TBoARD,

NGOs and communities as part of the extensive natural resources management, and moisture

conservation efforts in the region. It can be stated that the TBOARD has been trying to fix the

problems created by water from roads while the other sectors have little knowledge and

understanding on options of water harvesting from roads.

8.2 Stakeholder involvement

The ERA manual clearly states the following “Coordination between concerned agencies

during the project-planning phase will help produce a design that is satisfactory to all.

Substantial cost savings and other benefits can be realized frequently for highway and water

resource projects through coordinated planning among the various regional and local

agencies that are engaged in water-related activities (flood control and water resources

planning, etc.). Interagency cooperation through, for instance, the Ministry of Agriculture,

Ministry of Water Resources, and regional and local administrations, is an essential element

in serving the public interest”.

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However, from UPGro Catalyst research it was learned that there is less coordination among

the different stakeholders involved with road design and construction, water resources

development, agricultural, and environmental offices. Especially, the involvement of

communities in the planning and implementation of road development is non-existent.

9. Opportunities for water harvesting from roads

The potential for water harvesting is very high for the fact that:

§ Shallow groundwater is the main source of water for small-scale irrigation and

drinking in the area. One of the major problems with groundwater in the area is the

lowering of the water table especially in the dry season. Through proper management

of flood water from roads the groundwater could be recharged effectively.

§ The geohydrology of the areas is generally characterized by shallow unconfined

aquifer systems. The soil in the area is dominantly silty sand which makes it very

favorable for groundwater recharge. Groundwater systems could be enhanced through

a number of options which include: (a) construction of percolation ponds, check-

dams, and deep trenches, (b) controlled guiding of runoff from road sides, culverts

and bridges into farmlands in the form of spate systems, and (c) use of borrow pits as

surface water storage and groundwater recharge.

§ The communities along the roads have indicated that shortage of water is a critical

problem. Now that there is flood water from roads, it can be considered as an

opportunity rather than a threat if properly utilized for enhanced groundwater

recharge and retention.

§ Different organizations like TBoARD, NGO’s and the communities are actively

involved in natural resources management and moisture conservation activities in

Tigray. Moreover, the bureau of water resources is involved in water harvesting from

all sources while bureau of transport, road and construction is involved in road

development. So far those organizations involved in road design and construction and

those responsible for natural resources management and water resources development

have been operating independently. Runoff from roads is a major problem to the on-

going soil and water conservation efforts in Tigray. On the other hand, depletion of

shallow groundwater is a major concern of the bureau of water resources. There is

therefore a need for integrated planning and implementation of road development and

water harvesting through involvement of multi-stakeholders including communities.

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10. Recommendations: Design approach issues

This study has revealed that so far water from roads is considered as a threat not only in

the study area as well as in other parts of Ethiopia. The only efforts done so far to convert

these threats into benefits are those tried by the TBOARD, NGO’s and the communities.

It is therefore to consider the following design approaches in road development:

§ When planning road development in a certain catchment it is very important to

look at options on how water from a road is going to be harvested for economic

benefit of the local communities. This needs to be part of the TOR in the design of

the roads.

§ The location, alignment and size of drainage systems (culverts, etc) should be

designed with the objective of harvesting water from roads either to be collected

into surface water reservoirs or used for groundwater recharge. This requires a

comprehensive evaluation of the surface as well as subsurface geohydrology of

the areas.

§ Development of geological construction materials is one of the major activities in

road construction and this leads to creation of borrow pits. It is advisable that the

location and size of the borrow pit to be developed is identified during/or even

before the final design of the road is made. Based on this the locations of culverts

and even the road alignment could be designed in such a way that water from

roads (road side drainages, culverts, bridges etc) is channeled into borrow pits.

The option of using borrow pits as surface water storage as well as groundwater

recharge is one of the best alternatives to be considered as part of the road design

and construction.

§ Water harvesting from roads could be implemented effectively if road

development in a certain catchment is considered as part of the

watershed/catchment development plan. Through such approach, the possible

negative effects of water from roads and options for mitigating such problems

through water harvesting and natural resources management could be

implemented.

§ Water harvesting from roads involves multi-stakeholders. For water harvesting

from roads to be implemented effectively there should be strong linkages and

cooperation among the sectors through a more powerful body but with clear tasks

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and responsibilities for each stakeholder. From the catalyst grant it was learned

that the cooperation and linkages among the stakeholders is more important at

lower levels of the administration in which the final beneficiaries (communities)

are involved.