Research on the improvement of wetted perimeter method and application in seasonal rivers-a case study of Fenhe River, China.

Environmental flow is vital for maintaining river ecosystem health and ensuring the normal growth of aquatic organisms. The wetted perimeter method is indeed very useful in the assessment of environmental flow due to consideration of stream forms and minimum flow for aquatic life habitat. In this study, a river with obvious seasonality and external water diversion was selected as the typical research object; taking Jingle, Lancun, Fenhe Reservoir, and Yitang hydrological sections as control sections, we improved the existing wetted perimeter method in three aspects: (1) We improved the selection of hydrological data series. The selected hydrological data series should be of a certain length and can well reflect the hydrological changes of wet, normal, and dry years. (2) Different from the traditional wetted perimeter method, which only gives one environmental flow value, the improved method calculates the environmental flow month by month. (3) The improved wetted perimeter method establishes the relationship between native fish survival and environmental flow. Results indicated that the improved wetted perimeter took the survival of the main fishes into consideration, the ratio of the calculated results by the slope method to the multi year average flow was greater than 10%, which can ensure the fishes' habitat is not being destroyed, and the results are more reasonable. Furthermore, the monthly environmental flow processes obtained were better than the annual unified environmental flow value determined by the existing method and are consistent with the natural hydrological situation and water diversion situation of the river. This study shows that the improved wetted perimeter method is feasible for research of river environmental flow with strong seasonal and large variation of annual flow.

Do water shortages increase gastrointestinal nematode loads in Nguni does?

OBJECTIVE: The objective of the study was to assess the effects of water deprivation on the burden of gastrointestinal nematodes in Nguni does. METHODS: A survey was piloted on goat keepers in households where water was scarce (n = 143) and where it was available throughout the year (n = 142). In a controlled experiment, feed intake (ADFI), body condition score (BCS), FAMACHA score, packed cell volume (PCV) and faecal egg counts (FEC) were determined in does deprived of water for 24 and 48 h. RESULTS: There was a significant association between the frequency with which goats drink water and the distance from the water source. From the experiment, an increase in the water deprivation period decreased ADFI, BCS and PCV, and increased FAMACHA scores and faecal egg counts in Nguni goats. The BCS of goats deprived of water for 48 h was 12% lower than the control (p < 0.05). CONCLUSIONS: Reduction in water supply increased gastrointestinal burdens in does, which may compromise their productivity and production efficiency. Depriving goats of water for 24 h had no significant effect on gastrointestinal nematode (GIN) loads. The deprivation period of 48 h increased the GIN burden in does.

Farmer perceptions on factors influencing water scarcity for goats in resource-limited communal farming environments.

The objective of the study was to compare factors influencing water scarcity for goats in areas where there are seasonal and perennial rivers under resource-limited communal farming environments. Data were collected using a structured questionnaire (n = 285) administered randomly to smallholder goat farmers from areas with seasonal and perennial rivers. Ceremonies was ranked as the major reason for keeping goats. Water scarcity was ranked the major constraint to goat production in areas with seasonal rivers when compared to areas with perennial rivers (P < 0.05). Dams and rivers were ranked as the major water source for goat drinking in areas with seasonal and perennial river systems during cool dry and rainy seasons. Rivers were ranked as an important water source for goat drinking where there are seasonal and perennial river systems during the cool dry season. Households located close (≤ 3 km) to the nearest water source reported drinking water for goats a scarce resource. These results show that river systems, season and distance to the nearest water source from a household were factors perceived by farmers to influence water scarcity for goats in resource-limited communal farming environments. Farmers should explore water-saving strategies such as recycling wastewater from kitchens and bathrooms as an alternative water source. The government may assist farmers through sinking boreholes to supply water for both humans and livestock.