Effects of Land-Use Change on Characteristics and Dynamics of Watershed Discharges in Babeldaob, Palau, Micronesia

Table 1

Summary of physical parameters and sediment rates at the four watershed study sites.

Watershed	Size (km^2)	*Non forested area (km^2)	# of earthmoving permits (2000–2007)	Mean rainfall (mm month^−1)	River Flow Q (m^3 s^−1)	Sediment Flux; (kg s^−1)	Sediment Yield (tons km^−2 yr^−1)	**Sedimentation rate; (mg cm^−2 d^−1)	Mean SSC on reef (mg l^−1)	Peak SSC on reef (mg l^−1)
Diongradid	20.6	1.3	20	231	5.7	0.03	49.2	1.1	9	636
Ngermeduu	86.3	9.1	55	292	18.4	0.59; (0.19)***	215.7	4.6	139	1,123
Ngerdorch	47.4	7.8	15	235	3.8	0.01	9.7	1.8	2	24
Ngerikiil	28.5	2.8	168	312	7.2	0.42	462.4	4.1	38	943

*Mike Aurelio, David Idip, Jr. and Tarita Holm provided the data on nonforested area. The data were digitized from Quick Bird satellite image of Babeldaob. It was digitized as a shapefile using Arc view. Later the data was converted into arcinfo coverage.
**Data are from the first reef station with the highest sedimentation rate closest to the river mouth.
***Number in parenthesis indicates the sediment flux of one river. This number was multiplied by 3 to get total sediment flux for this watershed. This was done because only one of the three rivers that drain into Ngermeduu Bay was gauged and we assumed that all three rivers have about the same sediment flux, since their catchment areas and degree of development were similar.