19 Water Balance in Catchments
Josep Pinol, Anna Avila and Antoni Escarre
19.1 Introduction
Water balances in small catchments are widely used in forest science. Since
the watershed research at Wagon Wheel Gap (Colorado, USA) in 1910
(Cameron 1928), many other catchments have been instrumented to measure
precipitation inputs and runoff outputs. The main goal of this approach is to
evaluate the influence of vegetation cover on water yield, both in autocalibrated and in paired catchments. Reviews by Bosch and Hewlett (1982) and
Trimble and Weirich (1987) showed the negative relationship between forest
cover and water yield in catchments. The same result is obtained when forest
manipulations like clear-cutting or revegetation affect the entire catchment
(Hibbert 1971; Likens et al. 1977). When deep water losses are negligible because of the underlying lithology, the study of water balances in catchments
is the best technique to get accurate estimates of actual evapotranspiration.
Water precipitation input and streamflow output also provide the basic data
for the estimation of catchment element budgets (Chap. 20).
The objectives of this chapter are: (1) to compare the basic hydrology of
the holm oak (Quercus ilex L.) forest catchments at Prades and Montseny
with that from more humid areas; (2) to search for regularities in the interannual variation of streamflow and actual evapotranspiration; and (3) to
briefly discuss the validity of water balances obtained in small catchments
for larger areas, and the possible hydrological changes under a warmer climate.
The chapter summarizes the studies on the water balance conducted at
Prades and Montseny over the last 15 years. Part of the results have been
published (Avila and Roda 1990; Pinol et al. 1991, 1992, 1995), and the present work is mainly based on these previous studies. Nevertheless, data have
been updated by the inclusion of a new catchment (TMO at Montseny) and
more hydrological years both at Prades and Montseny. See Chapter 2 for a
description of the experimental catchments.
Ecological Studies, Vol. 137
Ferran Rodil et al. (eds) Ecology of Mediterranean
Evergreen Oak Forests
© Springer-Verlag, Berlin Heidelberg 1999
Josep Pinol, Anna Avila and Antoni Escarre
19.1 Introduction
Water balances in small catchments are widely used in forest science. Since
the watershed research at Wagon Wheel Gap (Colorado, USA) in 1910
(Cameron 1928), many other catchments have been instrumented to measure
precipitation inputs and runoff outputs. The main goal of this approach is to
evaluate the influence of vegetation cover on water yield, both in autocalibrated and in paired catchments. Reviews by Bosch and Hewlett (1982) and
Trimble and Weirich (1987) showed the negative relationship between forest
cover and water yield in catchments. The same result is obtained when forest
manipulations like clear-cutting or revegetation affect the entire catchment
(Hibbert 1971; Likens et al. 1977). When deep water losses are negligible because of the underlying lithology, the study of water balances in catchments
is the best technique to get accurate estimates of actual evapotranspiration.
Water precipitation input and streamflow output also provide the basic data
for the estimation of catchment element budgets (Chap. 20).
The objectives of this chapter are: (1) to compare the basic hydrology of
the holm oak (Quercus ilex L.) forest catchments at Prades and Montseny
with that from more humid areas; (2) to search for regularities in the interannual variation of streamflow and actual evapotranspiration; and (3) to
briefly discuss the validity of water balances obtained in small catchments
for larger areas, and the possible hydrological changes under a warmer climate.
The chapter summarizes the studies on the water balance conducted at
Prades and Montseny over the last 15 years. Part of the results have been
published (Avila and Roda 1990; Pinol et al. 1991, 1992, 1995), and the present work is mainly based on these previous studies. Nevertheless, data have
been updated by the inclusion of a new catchment (TMO at Montseny) and
more hydrological years both at Prades and Montseny. See Chapter 2 for a
description of the experimental catchments.
Ecological Studies, Vol. 137
Ferran Rodil et al. (eds) Ecology of Mediterranean
Evergreen Oak Forests
© Springer-Verlag, Berlin Heidelberg 1999