Newsletter and Technical Publications
of Alternative Technologies for Freshwater Augumentation
America and The Caribbean>
PART B. TECHNOLOGY PROFILES
1.4 Runoff Collection from Paved and Unpaved Roads
In countries like Brazil and Argentina, with semi-arid climates in which
the amount and frequency of precipitation are small and variable, it is
important to capture and store as much rainwater runoff as possible for
later use. In Brazil, runoff from paved and unpaved roads is captured by
street gutters and stored in subsurface galleries or dams strategically
distributed along the roadsides. Since 1935, underground barriers have
been built in Brazil to capture runoff. In 1965, an underground barrier
was built along the bed of the Trici River with the objective of storing
runoff water to provide water for domestic use in the municipality of
Taua. In Argentina and Venezuela, this technology has been used to provide
water for trees along the roadsides and for water-supply augmentation.
Paved and unpaved roads tend to shed water to their outside edges
because they are "crowned" or cambered. The runoff can be
captured in drainage ditches or underground galleries. A number of methods
have been used for this purpose. In most of these systems, the components
include a collection area, drainage system, storage area, and distribution
When formalized, most gutters are of trapezoidal shape with a length of
40 m, a width of 1 m, and an average depth of 1 m, as shown in Figure 9.
They are either parallel or perpendicular to the roads. The roadside
ditches store water temporarily, dissipate hydrologic energy through the
use of stones or other structures designed to slow the velocity at which
the water runs off the road surface, and convey the runoff to storage
areas. Storage areas may be constructed perpendicular to the drainage
ditches, and take the form of other conduits or underground galleries.
These are generally about 15 m in length and 1.3 m in depth and width. A
stone masonry wall is placed at the inlet of the gallery. This wall is
solid to a depth of approximately 0.8 m, below which the wall is
perforated to allow the water to enter the gallery while screening out
large particulates, animals, or debris. The base is a stone bed,
approximately 0.4 m thick.
In the Province of Mendoza, Argentina, runoff is collected and stored in
drainage ditches or V-shaped swales along paved roadways. Water harvested
in this manner is used primarily to cultivate trees planted in the swales.
The trees most commonly planted along the roadsides are carob and pepper
Paved roads are used also as dikes to divert runoff into impoundments
along the roadsides, as is done on the Macanao Peninsula in Venezuela.
Extent of Use
This method of runoff capture has been used in semi-arid regions of
Brazil, Argentina, and Venezuela.
Operation and Maintenance
The ditches and swales must be cleaned periodically by removing
branches, leaves, litter, and sediments. Ant infestation is a problem that
needs to be controlled in some areas. Whenever the roads are repaved or
rebuilt, the gutters, ditches, and/or swales should also be rebuilt or
repaired. The storage facilities, if used, should be inspected on a
regular basis, and cracks or other problems corrected. Litter and debris
should be removed from the gallery entrance.
Figure 9: A Schematic Representation of Runoff
Collection from Paved and Unpaved Roads, Using Underground Galleries for
Source: Everaldo Rocha Porto,
Level of Involvement
Government involvement is necessary since the water collected with this
technology is normally used to aid in the reforestation of public areas
and lands. Generally, construction and maintenance is managed by the roads
department, which is also responsible for road construction and
maintenance. In cases where the impounded water is used by the community,
private participation in constructing the water distribution system is
In Argentina, a forestation project on both sides of a 1 km stretch of
paved road cost about $2 000. Costs will vary as a function of the length
of roadway treated and the characteristics of the pavement. Provision of a
distribution system, if required, could increase the cost per kilometer
Effectiveness of the Technology
The application of this technology as a means of supplying moisture for
plantings along roadsides in the Province of Mendoza, Argentina, was very
successful. During the period from 1985 through 1995, carob trees grew an
average of 30.7 cm/year and pepper trees an average of 35 cm/year during
the same period.
The technique is suitable for use in arid and semi-arid rural areas
where runoff from paved and unpaved roads can be collected and stored.
- Runoff collection and storage enhance the flora and fauna of a
- Runoff collection can enable cultivation in arid and semi-arid
- The technology has a low operating cost; the capital cost can be
subsumed in the cost of constructing the road.
- It is easy to operate and maintain.
- It reduces erosion and controls sedimentation.
- Plants may require supplemental irrigation during dry periods.
- Animals must be kept away from the plantings to avoid plant damage.
- It requires appropriate soil conditions.
- Water collected from roadways may be contaminated by litter and
debris and in the urbanized areas by chemical pollutants from vehicles.
This technology is well accepted by public works departments in arid and
semi-arid areas. Communities in those areas also support the technology.
Further Development of the Technology
This technology should be combined with some of the in situ or
regional impoundment techniques to improve the efficiency and utilization
of runoff capture and storage. Since it is a simple and low-cost
technology, its use should be encouraged.
Armando R. Pedrani, Coordinador del Programa de
Investigación y Desarrollo, and Alberto I. J. Vich,
Investigador Adjunto del Programa de Investigación y Desarrollo:
Manejo Ecológico del Piedemonte (Mendoza), Instituto Argentino de
Nivología, Glaciología y Ciencias Ambientales, Unidad Ecología
y Manejo de Cuencas Hidricas, Casilla de Correo N° 330, 5500 Mendoza,
Argentina. Tel. (64-61)28-7029. Fax (64-61)28-7029 / 28-7370. E-mail:
Everaldo Rocha Porto, Luiza Teixeira de Lima Brito, and
José Barbosa dos Anjos, Empresa Brasileira de
Pesquisa Agropecuária (EMBRAPA), Centro de Pesquisa Agropecuária
do Tropico Semi-Árido (CPATSA), BR-428 km 52, Zona Rural, Caixa
Postal 23, 56300-000 Petrolina, Pernambuco, Brasil, Tel. (55-81)862-1711.
Fax (55-81)862-1744. E-mail: email@example.com,
firstname.lastname@example.org, and jbanjos@cpatsa. embrapa.br.
Aderaldo de Souza Silva, Empresa Brasileira de Pesquisa
Agropecuária (EMBRAPA), Centro Nacional de Pesquisa de
Monitoramento e Avaliacao de Impacto Ambiental (CNPMA), Rodovia SP-340 km
127.5, Bairro Tanquinho Velho, Caixa Postal 69, 13820-000 Jaguariuna, São
Paulo, Brasil. Tel. (55-0198) 67-5633. Fax (55-0198) 67-5225.
Carmen Fermín, Dirección de Hidrología
y Meteorología, Esquina Camejo, Edificio Camejo, 5º piso,
Caracas, Venezuela. Tel. (58-02)408-1952. Fax (58-2)5450607. E-mail:
Cuomo, A.R., and M.A. Palermo. 1987. Introdução as Técnicas
de Correção de Cursos d'Água Torrenciais. São
Paulo, Universidade de São Paulo, Centro Tecnológico de Hidráulica
da Escola Politécnica. (Boletim 6)
Departamento de Aguas y Energia Eléctrica do Estado de São
Paulo (DAEE). 1988. Relatório sobre a Atuação da
Comissão Especial para a Restauração da Serra do Mar
em Cubatao. São Paulo.
Lloret, C.L., and M.A. Palermo. 1989. "Critérios para Avaliação
de Impactos Ambientais em Obras de Correção de Cursos d'Água."
In Anais do VIII Simpósio Brasileiro de Hidrologia e Recursos Hídricos,
Foz do Iguaçu, Brasil. São Paulo, Associação
Brasileira de Recursos Hídricos.
National Academy of Sciences. 1974. More Water for Arid Lands:
Promising Technologies and Research Opportunities. Washington, D.C.
Pérez Hernández, David. 1994. Aprovechamiento del
Embalse San Francisco y Otras Fuentes Alternas de Agua en Macanao, Estado
Nueva Esparta. Caracas, MARNR.
Pica, M. 1972. "Su Alcumi Aspetti de Transporto Solido in Alvei
Torrentizi," L'Enegia Elettrica, 8, pp. 497-508.
Public Works Department of Western Australia. 1956. "Roaded
Catchments for Farm Water Supplies," Western Australia Department
of Agriculture Agricultural Journal, 5(6), pp. 667-679.