Kingston University Biodiversity Action Group

21-01-15: (Kingston) - A river runs through it

What we associate with the Hogsmill River- download the full feedback sheet from the Hogsmill Partnership meeting here

Last Wednesday Riverfly Monitoring volunteers and other stakeholders attended the inaugural River Hogsmill Forum at London Zoo.

The forum is an opportunity to discuss the results of monitoring on the river, highlight new partnership opportunities, projects and training and emphasise issues on the Hogsmill. It works hand in hand with the Hogsmill Partnership to align local efforts to achieve “A clean river, rich in biodiversity, that is a resource for an engaged local community”.

A shared vision for the future of the Hogsmill

There were interesting talks from the Zoological Society of London (ZSL) South East Rivers Trust (SERT), Thames Water and the Environment Agency (EA) with a training opportunity for a new Pollution Monitoring project which I’ll tell you more about in a bit…


While you should be familiar with the Hogsmill as it runs right through Kingston, it’s classed as a heavily modified water body given its very urban location and this brings with it many problems including pollution, habitat degradation and habitat fragmentation. Here’s a little image containing 5 facts about the river, see if you can work out all of them – post your answers in the comments below.

During the first of the ZSL talks the presenter highlighted that, in terms of chemical water testing, phosphate levels are relatively high in the Hogsmill.   Phosphates are key nutrients stimulating the growth of plants and algae in the river and are found in relatively high concentrations in sewage. Excessive inputs of such compounds are known to limit river biodiversity (eutrophication) so actions need to be taken to reduce phosphate concentrations.  As well as effluents from the Hogsmill Sewage Treatment Works and sewer overflows, evidence suggests that misconnected home drainage is a key way in which untreated effluents get into the Hogsmill.

More interestingly they mentioned the pollutant Triclosan as having a major affect in rivers and its one of the chemicals that we have failed tests for in the Hogsmill. If like me you hadn’t heard of this as a pollutant in rivers – it’s an antibacterial and antifungal agent found in products such as soaps and detergents. Its presence can often be attributed to misconnections in household drains by builders, plumbers and DIY enthusiasts resulting in water which should be going down the sewer drain (water from toilets with raw sewage, washing machines with chemical detergents, baths and showers with all of the chemicals we use for bathing and cleaning), going straight into the river without any treatment!

The full effects of this chemical are potential risks of increased bacterial resistance and toxicity to wildlife. More info for those interested can be found on Wiki

While the EA conduct monthly checks on the river, these are all at one fixed point rather than across the whole river which has limitations. They reiterated the importance of initiatives such as the RMI monitoring and new pollution monitoring projects combined with the public reporting issues, as being of vital importance to fill gaps in data and knowledge.

ZSL's RMI update

All of the monitoring of the river over the last year at the 4 current monitoring locations (Middle Mill, Green Lanes, Green Lanes Bridge and the Ewell Storm Tank) has resulted in the setting of the Hogsmills Trigger Level of 5 (the score ranges from 0-10). Any monitoring that comes out below this score will result in an incident report being made to the EA.

The following table compares our score results to that of the Rivers Wandle and the Crane

Average for the overall site
Range of averages on the river

Our river is comparable with the Wandle given that both are heavily modified urban rivers, so the smaller range of averages across all of the sites, with the average scores being in the upper range seems to imply that the river is doing okay in terms of health at these monitoring sites on the Hogsmill. As more monitoring sites come online it will be interesting to see if this is maintained. 

New pollution monitoring project and training opportunity

SERT are launching a new pollution monitoring project, getting local residents and site users to undertake quick weekly/fortnightly checks (may take around 5-15/20 minutes a week). The project comes with free training and is a great opportunity to get involved if you study/work or live near the river. 

Kingston University has two campuses (Knights Park and Penrhyn Road), two halls of residence (Kingston Bridge House and Middle Mill) and two offices (Cooper House and River House) within a very short walk or a stones throw from the river. 

We are hoping to run one of the free courses at the University if there is enough demand, so please get in touch with me to let me know if you would be interested so that I can email you the date once its confirmed for Feb/March 2015.

Hogsmill Sewage Treatment Works

Thames Water talked about the Hogsmill Sewage Treatment Works (HSTW), located approximately 500 meters upstream of the Uni. They talked about the process undertaken to clean the sewage, but also the other ways that pollutants bypass the treatment areas and go directly into the rivers. The first being misconnections –another interesting fact for a pub quiz - it has been calculated that an average of 16 Olympic swimming pools worth of raw sewage and foul water is entering Britain’s rivers every day due to misconnections.

The second being surface water sewers which handle Rainwater from roof, driveway, patio, roads, etc. These run directly into rivers due to the historic way the system was built and the belief that surface runoff was less harmful then foul water. However the issues for surface water are the chemicals from roads and gardens that enter this system such as brake fluid, heavy metals etc. These cause major issues in the environment that have only been highlighted in the 20th century long past the point when the drains system was built!

The final talk by the EA gave us an overview of the Water Frameworks Directive which is the driving bit of EU legislation targeting river improvements. The target is for all rivers to have a status of good (five possible statues of Bad, Poor, Moderate, Good and High) between 2015 and 2021.
They mentioned an important consultation currently out for comment

A draft River Basin Management Plan which can be found here and a summary of what the document is and why your input matters is located here

1 comment:

  1. Length: 9.9km
    Catchment: 73km^2
    Tributaries: 5
    Boroughs run through: 3
    Tributary to: River Thames