Monthly macrophyte surveys of the CEH River Lambourn Observatory at Boxford

This study has resulted in the collection of a unique dataset of seasonal macrophyte growth over a six year period, encompassing extreme levels of flow both high and low. Although not analysed the results of the surveys are presented in this report. The data collected would enable subsequent investigation of the impact of weed cuts on the composition, density, cover and recovery time of these species and the relationship between macrophyte growth, hydraulic roughness, flow regimes and sediment transport/deposition

Use of hydraulic rating to set environmental flows in the Zhangxi River, China

Ningbo city, China, is a rapidly growing residential and industrial centre, with a current population of 4 million. Its development has required a major water supply expansion programme providing 400,000 m3 of water per day from the upper reaches of the Zhangxi River by means of a cascade of reservoirs. Water resources management is achieved through operation of two major reservoirs, Jiaokou (75 million m3) and Zhougongzhai (93 million m3). Water is released from the reservoirs, via turbines (generating hydropower), for local industry, irrigated agriculture and public supply along the lower reaches of the River and to maintain the river ecosystem. Surveys of local residents along the Zhangxi River showed its important role in aspects of life, social activity, culture and leisure. Analysis of ecological monitoring data demonstrated the diverse nature of fish, plants and invertebrates within the river. Some elements of the ecosystem have a high local economic value to local people. This paper reports an assessment of the environmental flow needed to support key species in the river ecosystem. It employs hydraulic ratings to define sections of the river where flow velocity reaches 0.5 ms-1, required to stimulate spawning of the moonlight fish, an economically important and indicator species in the river. In two out of 6 cross-sections studied, flow releases from the reservoirs meet the needs of fish. The reservoirs reduce flood flows, which may lead to a loss of deep pools that are essential for the fish to survive during winter month

Effects of drip-irrigation regimes with saline water on pepper productivity and soil salinity under greenhouse conditions

The aim of this study was to investigate the response of sweet pepper (Capsicum annuum L.) to saline irrigation water and various irrigation regimes. The experiments were conducted in a greenhouse with two sweet pepper varieties (ONUR F1 and ADA F1) over two cropping seasons: spring and autumn on the Mediterranean coast at Antalya, Turkey. The irrigation regimes comprised four levels of Class A pan-evaporation and were applied using a drip irrigation system when evaporation reached a target value of around 10 mm. These four levels represented 0.50, 0.75, 1.00 and 1.25 of Class A pan-evaporation. In each irrigation regime the sweet pepper plants were exposed to four salinity treatments with electrical conductivities of 1.0, 2.5, 3.5 and 6.0 dS m−1 respectively. The study showed that both pepper varieties generally performed in a similar manner (except in terms of vegetative biomass production). The amount of salt accumulation within the root-zone was higher in spring compared to autumn; and therefore related to the total amount of irrigated water usage between seasons due to climatic variability. Increased salinity induced higher levels of salt accumulation within the pepper plant’s root-zone, while an increased amount of saline irrigation water increased the size of the affected layer within the root-zone. Overall, an increased level of salinity alongside increased irrigation considerably depressed both vegetative growth and yield. Higher irrigation water productivities were attained with a regime comprising 0.50 of Class A pan-evaporation and which appeared to fulfil crop water requirements. It was found that sweet pepper varieties ONUR F1 and ADA F1 are moderately sensitive to salinity with a threshold value of 1.43 dS m−1 and a decreasing slope value of 11.1%. Although both seasons revealed a single salinity response function, there were considerable differences in the actual fresh pepper yield. This study demonstrates that for pepper crops irrigated with saline water (or grown on salt-affected soils), pepper growers must consider the salinity response function and seasonal productivity alongside an appropriate irrigation regime

Wetland hydrological monitoring: overview and Boxford Water Meadows case study

The aim of this report is to provide the reader with the information required to make informed decisions about the best and most appropriate way to monitor a wetland site. To achieve this aim, the report has the following objectives: 1. To outline the need and purpose for monitoring. 2. To summarise the methods used to identify and categorise wetland types. 3. To describe the broad types of monitoring that may be undertaken. 4. To give detailed information about the range of wetland monitoring techniques available. 5. To provide guidance on how to select the most appropriate monitoring techniques. 6. To illustrate, using the Boxford wetland as a case study, how the techniques described in this report can be applied, and what challenges and solutions are encountered

Tolerance of faba bean, chickpea and lentil to salinity: accessions' salinity response functions

The productivity of crops irrigated with saline water or grown on salt-affected soils depends on the salt tolerance of the crops, their accessions, and various environmental and cultural conditions such as soil properties, climate and irrigation methods. The level and ability of plants to tolerate salt stress is the most critical information for the successful management of salt-affected agricultural lands and saline irrigation waters. In this paper, responses of three food legume crops (faba bean, chickpea and lentil) to salinity stress were analysed using the threshold-slope linear response function and modified discount function. The response functions are calibrated using the 2009–2010 season data and validated using the 2010–2011 season data from faba bean, chickpea and lentil experiments conducted in Raqqa, Syria. The comparison was also made through SALTMED model predictions. The results of this study show that the salinity response functions and productivity of grain yield are highly variable within the accessions of the same crop. For optimum outcome, practitioners need to consider salinity response functions and also the productivity of different accessions and their response to salinity in relation to the soil and available irrigation water salinity level

Hydrodynamic Behaviour of a Two-Stage Channel with Horizontal and Inclined Floodplains: A Numerical Investigation

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv