Agricultural Water Management 131 (2014) 156–162 Contents lists available at ScienceDirect Agricultural Water Management j ourna l h o me pa ge: www.elsevier.com/locate/agwat Estimating the contribution of in-stream cattle faeces deposits to nutrient loading in an English Chalk stream Trevor Bond a,∗ , David Sear a , Tim Sykes b a University of Southampton, Geography and Environment, Building 44, Highfield SO17 1BJ, United Kingdom b Environment Agency, Romsey District Office, Canal Walk, Romsey, Hampshire SO51 8DU, United Kingdom a r t i c l e i n f o Article history: Received 1 April 2013 Accepted 18 August 2013 Available online 25 October 2013 Keywords: Water quality Chalk stream Nutrient loading Faeces Cattle a b s t r a c t Numerous studies have shown that the addition of faecal matter from livestock to aquatic ecosystems can have a detrimental effect upon water quality. English Chalk streams, as groundwater-dominated rivers of high ecological importance, are particularly susceptible to nutrient loading from cattle faeces. Naturally low concentrations of nitrogen, phosphorus and potassium in such rivers increase their vulnerability to external perturbation from organic matter inputs. Despite this, the amount of faeces directly contributed by livestock such as cattle to a river system is rarely quantified. To provide an assessment of nutrient loading due to cattle, a study combining observational data of animal behaviour with faecal analysis was undertaken in an English Chalk stream. Results show that cattle faeces was 89.4% water, containing 0.79% nitrogen, 0.43% phosphorous and 0.43% potassium by wet mass. It was estimated that a herd of 33 cattle deposited over 8 tonnes of faeces into a 770 m river reach over a seven-month period in 2010. This loading is estimated to have increased in-stream nitrogen, phosphorus and potassium concentrations in the reach by 0.0036 mg l -1 , 0.002 mg l -1 and 0.002 mg l -1 respectively; a small proportion of the overall nutrient content of the river. Moreover, it has been demonstrated that by combining behavioural data with faecal data it is possible to estimate the likely nutrient loading due solely to direct inputs from cattle faeces. With sufficient data, calculations such as those employed in this study can be used to provide accurate estimates of the nutrient loading due to livestock in watercourses. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Direct and indirect inputs of organic material from cattle faeces and urine to watercourses have been of interest to land managers for several decades (Doran and Linn, 1979; Gary et al., 1983). How- ever, the most well researched aspect of water quality changes induced by cattle excrement pertains to human health, and specif- ically the prevalence of Escherichia coli bacteria in water (Collins and Rutherford, 2004; Davies-Colley et al., 2004). Where nutri- ent loading indicators such as nitrogen and phosphorus have been measured, investigations are often concerned with pathogens and disease; methemoglobinemia (blue baby disease) and carcinogenic materials from nitrogen, and the threat of cyanobacteria poisoning from phosphorus induced eutrophication (Hubbard et al., 2004). Moreover, the majority of existing studies have been conducted in the rangelands of Australasia and North America, where river ∗ Corresponding author at: School of Geography, University of Southampton, SO17 1BJ, United Kingdom. Tel.: +44 07905 731 317. E-mail addresses: Trev.Bond@soton.ac.uk, trev.bond@environment-agency.gov.uk, t.a.bond@hotmail.co.uk (T. Bond). characteristics and cattle herd size are generally different to those of southern England’s lowland Chalk streams (Fleischner, 1994; Davies-Colley et al., 2004; Monaghan et al., 2005). English Chalk streams are recognised internationally for their ecological status; England has the greatest length of Chalk streams in Europe, with 161 Chalk streams in England spanning from the River Hull in Humberside to the River Frome in Dorset, and 10 Chalk stream Sites of Specific Scientific Interest (Environment Agency, 2004). Chalk streams are groundwater-dominated and therefore exhibit high water quality, with low suspended sediment con- centrations, high water clarity and comparatively stable thermal regimes (Mackey and Berrie, 1991; Sear et al., 1999; Webb and Zhang, 1999; Heywood and Walling, 2003). Natural background values of nutrients such as phosphorus, nitrogen and potassium are relatively low in Chalk streams, but can be raised due to sewage and other allochthonous inputs from agricultural land-use, with unde- sirable consequences (Casey et al., 1993; Bowes et al., 2005; Jarvie et al., 2008). Phosphorus concentrations in Chalk streams have fallen over the past 20 years as a result of phosphorus stripping at sewage works and changes in land-use practices (Young et al., 1999; Hanrahan et al., 2003; Neal et al., 2010; Bowes et al., 2011). Typical 0378-3774/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.agwat.2013.08.015