Geoscience Reference
In-Depth Information
values for these dissolved nutrients are generally lower than those for dissolved
ions and solid (Table
9.1
). The result indicates that although the ability of PDLU to
explain the spatial variation in dissolved ions and solid vary greatly across the study
area, PDLU exhibits stronger abilities to explain the variance in dissolved ions and
solid than to explain the variance in dissolved nutrients, especially in less-urbanized
areas. Therefore, the results suggest that developed land has more adverse impact
on water quality, especially on the concentrations of dissolved ions and solid, in
less-urbanized watersheds than in highly-urbanized watersheds. Same amount of
increase in percentage of developed land may cause higher increase in concentra-
tions of dissolved ions and solid in less-urbanized areas than in highly-urbanized
areas.
9.5.3 Relationships Between Population Density and Water Quality
Figure
9.6
shows the values of
t
-test on the local parameter estimates for population
density obtained from the GWR models. Although negative correlations are found
between population density and some water quality indicators at some sites, none
of them are significant (Table
9.1
and Fig.
9.6
). Significant positive correlations
Fig. 9.6
Results of
t
-test on the parameter estimates for population density from the GWR models
(The
t
-values for NH
3
-N and K are positively significant at
p
<0.05 at all sampling sites; the
t
-value
for NO
2
-N are positively significant at
p
<0.05atmostsamplingsites)
