2
that peak monthly effective rainfall corresponded to peak monthly runoff.
Furthermore, a review of rainfall-runoff relationships is supported by previous
researches, such as: Xu 1997, Xu and Singh 1998, Strasser and Mauser 2001, and Li
2005.
Table 1. Rainfall-runoff relationships in the Western Ghats in South India
Watersheds Rainfall
mm
Observed Runoff
mm
HonamanaHalla YettinaHole
KonganaHole Lakshmanatirtha
Malathi Harangi
Hemavathi 1447
3044 2461
2429 5660
3177 2888
895 2099
1639 1667
4701 1929
1959
Source: Putty and Prasad 2000
2. 4 Relationships between runoff and land covers
A long term study in the Weser catchments, Germany showed that maximum
runoff occurs in the mountainous regions 600 mm, where intensively covered by forest
followed by settlements 400 mm due to their small actual evapotranspiration AET and
infiltration capacity Strasser and Mauser 2001. A study in Lestijoki catchment,
Finland reported that forests areas contribute greater runoff than peat and field, because
forests were the most common land cover types in the catchments Karvonen 1999.
Hence, the relationship between land cover and runoff has also shown in Kurnianto
2004.
Management of wetland forest on cypress-pine flatwoods in the southern United
States described runoff from the maximum disturbance watershed was significantly
higher but reduced from 150 - 65 after the management was undergone Sun 2001. In
the investigation of forest conversion from eucalypts to Pinus radiata by Putuhena and
Cordery 2000 showed that runoff decreased as the plantation grew. Research in South
Island, New Zealand described an estimated reduction in runoff of 340 mm within 5 years
at one of their catchments studied Fahey and Jackson 1997. Calder 2002 gained a new
understanding of evaporation from forests in dry and wet conditions based on process
studies. Those studies indicate decreased runoff from areas under forest as compared
with areas under shorter crop. However, cloud forest and very old forest was excluded from
the description above. Kaimowitz 2004 argued that the water falling will be grater
infiltrated than quickly running off in the well established forest cover. Studied by Sun
2002 in tree forest ecosystem in the Southern US reported that runoffrainfall ratio
was greater in upland than in wetland areas. A studied that had examined runoff-dependent
of forest types by Ollinger 1998 described that runoff was generally higher for hardwood
than coniferous forest. In addition, the Mountain Ash species Eucalyptus regnans
showed the affect between forest age and catchments water balance, where annual
runoff increased from 429 mm at age 15 years to 889 mm at age 240 years Vertessy 2001.
Another studied in Mountain Ash shows that runoff was smaller when the regenerating
forest was aged 13-16 years Cornish and Vertessy 2001.
2. 5 Relationships between runoff and soil
