By scouring experiments, the changeable process and characteristics of sediment concentration in sloping surface with different coverage degrees and spatial locations of grass were studied. Five grass coverage degrees of 0, 30%, 50%, 70%, 90%, three spatial locations of grass (upslope, mid-slope, low-slope) and two water inflow rates of 3.2L/min, 5.2L/min were applied to a 0.5 by 8 m soil bed in scouring experiments. Results showed that in the hillslope–gully side erosion system, the grass coverage has great effect on reducing the sediment concentration in the overland flow when the water inflow rate is small, but when the water inflow rate is large this kind of effect is very limited. When the grass located at the low-slope on the hillslope the sediment concentration is relatively smaller. The sediment concentration in the overland flow is gradually decreasing with the duration of scouring, and the effect of spatial locations of grass on the temporal variation of sediment concentration is very complicated because of gully erosion.

Analysis and study were carried out by means of mathematical statistics on sediment reduction effect by soil retaining dam with different storage capacity allocation proportion in Dali river watershed of the Yellow River. The results indicate that, sediment reduction by large, middle and small soil retaining dam account for 80.1%, 14.6%, 5.3% of the total reduction; the sediment reduction benefit has reached its maximum since 1990s, amounting to 30.2%, with corresponding storage allocation proportion of 1.84:2.37:5.79.Dam and reservoir have obvious influence on the correlation between rainfall and sediment in the river watershed, sediment transport is reduced by 10 million ton corresponding to annual average flood season rainfall of 350mm in the watershed. Within the sediment reduction capability of soil retaining dam, the sediment reduction volume increase with more rainfall in the flood season, having the feature of the more incoming sediment is, the more sediment reduction will be.

Morphological development of rill at hillslope formed a microrelief dynamic response system with soil erosion driven by rainfall. To reveal the formation mechanism of this system, scientifically quantification is the key problem. In recent years, domestic and foreign scholars had achieved fruitful results in rill evolution and quantized fields. This paper analysised the existing problems in the present research based on summarizing the current existing methods of rill morphology quantitation, and put forward the research direction in the future.

By scouring experiments, the changeable process and characteristics of sediment concentration in sloping surface with different coverage degrees and spatial locations of grass were studied. Five grass coverage degrees of 0, 30%, 50%, 70%, 90%, three spatial locations of grass (upslope, mid-slope, low-slope) and two water inflow rates of 3.2L/min, 5.2L/min were applied to a 0.5 by 4 m soil bed in scouring experiments. Results showed that the sediment concentration in overland flow obviously decreased with increasing grass coverage degree during the scouring experiments. When the grass coverage degree is over 30%, the grass can play obvious role in reducing the sediment concentration, and along with the increase of grass coverage degree the role became more and more obvious, particularly when the grass coverage degree reached to 70%. The spatial location of grass on the sloping surface has little effect on the sediment concentration in overland flow.

The characteristics of biological nutrient removal was investigated with aerobic granular sludge in an anaerobic/aerobic SBR system. The anaerobic/aerobic SBR system showed a very stable phosphorus, nitrogen and organic carbon removal performance. The average removal rate for NH4+-N, total inorganic nitrogen (TIN), PO43--P and CH3COO--C reached 97.8%, 89.7%, 96.8% and 98.8%, respectively, when dissolved oxygen concentration in the aerobic phase was controlled at 1~2mg/L, with 80~90min anaerobic phase followed by 240min aerobic phase during the SBR cycle. The nitrification, denitrification, aerobic phosphate uptake and anoxic phosphate uptake could occur simultaneously in aerobic granular sludge under aerobic condition. The microorganism population in the granular sludge has a diversification, the formed microecosystem is more stable and the ability to withstand shock loading and the self-regulation ability are stronger.