Using high-frequency phosphorus monitoring for water quality management: a case study of the upper River Itchen, UK

Abstract

Increased concentrations of phosphorus (P) in riverine systems lead to eutrophication and can contribute to other environmental effects. Chalk rivers are known to be particularly sensitive to elevated P levels. We used high-frequency (daily) automatic water sampling at five distinct locations in the upper River Itchen (Hampshire, UK) between May 2016 and June 2017 to identify the main P species (including filterable reactive phosphorus, total filterable phosphorus, total phosphorus and total particulate phosphorus) present and how these varied temporally. Our filterable reactive phosphorus (considered the biologically available fraction) data were compared with the available Environment Agency total reactive phosphorus (TRP) values over the same sampling period. Over the trial, the profiles of the P fractions were complex; the major fraction was total particulate phosphorus with the mean percentage value ranging between 69 and 82% of the total P present. Sources were likely to be attributable to wash off from agricultural activities. At all sites, the FRP and Environment Agency TRP mean concentrations over the study were comparable. However, there were a number of extended time periods (1 to 2 weeks) where the mean FRP concentration (e.g. 0.62 mg L −1) exceeded the existing regulatory values (giving a poor ecological status) for this type of river. Often, these exceedances were missed by the limited regulatory monitoring procedures undertaken by the Environment Agency. There is evidence that these spikes of elevated concentrations of P may have a biological impact on benthic invertebrate (e.g. blue-winged olive mayfly) communities that exist in these ecologically sensitive chalk streams. Further research is required to assess the ecological impact of P and how this might have implications for the development of future environmental regulations.

Mathematical modelling for the phosphate and nitrate carrying capacity of dams in Uttarakhand

“…In a case study of upper Itchen, (UK), some researchers monitored phosphorus for water quality management. It was suspected that recently increased phosphorus concentration was found in environmental degradation (Fones et al, 2020). A day after Typhoon Lekima swept across the coastal parts of Penang, Malaysia, in August 2019, mass fish mortalities were documented, resulting in massive losses among fish farmers.…”

Data-Driven System Dynamics Model for Simulating Water Quantity and Quality in Peri-Urban Streams

“…The simulation of DO concentrations at the sub-daily time step highlights the need for improved characterization of the influence of the aquatic plant biomass, both in terms of spatial coverage but also in terms of autotroph group dynamics, to fully capture the overall dynamics of DO in small peri-urban streams. This task, however, may need to rely on more spatially detailed and high-frequency data, very often not available [81,100]. Furthermore, the observed time shift for the diel oscillation cycle points towards potential uncertainty in the reaeration formulation.…”

The fractionation of phosphorus in UK chalk stream surface waters and its relevance to the regulation and management of water quality

“…Regarding temporal aspects, the inventory and desk-based study should evaluate potential sources of P in term of their potential for chronic or acute impacts of P on surface waters. In the case of acute discharges, monthly sampling (UKTAG 2013(UKTAG , 2014 is unlikely to indicate the presence, duration and severity of sporadic events; site-specific and high frequency sampling may be necessary (Fones et al 2020). Consideration should also be given to seasonally-dependent facets; periods of higher insolation can influence the uptake of P by photosynthetic organisms, which in turn affects the balance between P fractions of different size and reactivity.…”