7.3 Methods and Materials
99
Runoff experimental plot
3
4
1
2
Runoff observation station
Rainfall observation station
Scale
1.0 km
0.5
0
(a)
(b)
(c)
Fig. 7.2 Precipitation observation stations, runoff observation stations, and runoff plots in the
Nanxiaohegou Catchment. Adapted from Tian et al. (2008). a A sketch map of the Nanxiaohegou
Catchment; b Runoff plots; c Runoff observation stations. Keys: 1. Shibamutai Reservoir runoff &
rainfall observation station; 2. Qiugou runoff experimental plots; 3. Huaguoshan Reservoir runoff
& rainfall observation station; 4. Dongzhuanggou runoff and rainfall observation station
soil or water was generally calculated according to the reservoir capacity or the
farmland area.
In general, the effects of soil and water conservation practices are discussed based
on the amounts of retained soil, water, and soil nutrients. In the present work, three
indexes are defined to describe the effects: (1) retention ability, representing the
amount retained by a certain conservation practice per unit area per year, (2) total
retention efficiency (TRE), representing the ratio of the total amount retained by all
conservation practices to the total transport amount in a year, and (3) retention ratio,
99
Runoff experimental plot
3
4
1
2
Runoff observation station
Rainfall observation station
Scale
1.0 km
0.5
0
(a)
(b)
(c)
Fig. 7.2 Precipitation observation stations, runoff observation stations, and runoff plots in the
Nanxiaohegou Catchment. Adapted from Tian et al. (2008). a A sketch map of the Nanxiaohegou
Catchment; b Runoff plots; c Runoff observation stations. Keys: 1. Shibamutai Reservoir runoff &
rainfall observation station; 2. Qiugou runoff experimental plots; 3. Huaguoshan Reservoir runoff
& rainfall observation station; 4. Dongzhuanggou runoff and rainfall observation station
soil or water was generally calculated according to the reservoir capacity or the
farmland area.
In general, the effects of soil and water conservation practices are discussed based
on the amounts of retained soil, water, and soil nutrients. In the present work, three
indexes are defined to describe the effects: (1) retention ability, representing the
amount retained by a certain conservation practice per unit area per year, (2) total
retention efficiency (TRE), representing the ratio of the total amount retained by all
conservation practices to the total transport amount in a year, and (3) retention ratio,