Editing River Mole (section)

===Water quality===
Standard water quality of Mole and its tributaries has improved markedly since the 1990s.  In 1990 the [[Environment Agency]] assessed 23% of the watercourses as Grade B (good) or better.  In 2002 this figure was 60%.<ref name=CAMs/>  Investment in the Sewage Treatment Works in the catchment area has improved the quality of the discharges into the river,<ref name=CAMs/> and modifications to the runway and apron drainage systems at [[Gatwick Airport]] mean that surface water is diverted to aerated pollution control lagoons and [[balancing lake|balancing pond]]s for treatments, including acid/alkali neutralisation, before release into the river.<ref>{{cite web |url= http://www.gatwickairport.com/PageFiles/202/corpresponse/BAA%20Gatwick%20Corporate%20Responsibility%20Report%2005-06.pdf |title= Gatwick Airport Corporate Responsibility Report |author= Griffifths P |year= 2006 |publisher= London Gatwick Airport |access-date= 5 January 2011 |archive-url= https://web.archive.org/web/20100923033214/http://www.gatwickairport.com/PageFiles/202/corpresponse/BAA%20Gatwick%20Corporate%20Responsibility%20Report%2005-06.pdf |archive-date= 23 September 2010 |url-status= live }}</ref>

In 1972 a sub-debate on the future cleanliness of the Mole was had by the [[House of Lords]], involving a member of the [[South-East Strategic Committee]] of the [[Thames Conservancy]] (succeeded by the [[Environment Agency]]) and four others.  In this it was said, "...I can see no future for [The Mole]. The Mole Valley has been polluted. The Mole where I used to tickle [[trout]] in my youth is a drain, and it will remain a drain." Rebuttals included that the Mole is a "charming Surrey steam" and "If [[Earl of Lytton|Lord Lytton]] went to fish in the River Mole – and there are still angling clubs there – he would find that he would still be able to catch a [[trout]]".<ref>{{ukhansard | house=HL | date= 11 September 1972 | vol=335 | cc=138-165}}</ref>

Highly polluting discharges have become less common but have taken place since 2000. In 2003, Gatwick Airport Ltd pleaded guilty to charges of allowing chemical pollution to enter the River Mole after a detergent, used to clean rubber and oil from the runway, was washed into Crawters Brook by airport workers.<ref>{{cite news |url=http://news.bbc.co.uk/1/hi/england/southern_counties/3237285.stm |title=Airport Guilty of Killing Fish |date=November 2003 |work=[[BBC News Online]] |access-date=10 February 2010 |archive-url=https://web.archive.org/web/20031211213351/http://news.bbc.co.uk/1/hi/england/southern_counties/3237285.stm |archive-date=11 December 2003 |url-status=live }}</ref> The [[Environment Agency]] estimated that up to 5200 fish of 14 different species were killed as the pollution drained downstream.  The airport was fined £30,000 by [[Lewes]] [[Crown Court]].<ref>{{cite news |url=http://news.bbc.co.uk/1/hi/england/southern_counties/3456215.stm |title=Airport Fined for Killing Fish |date=February 2004 |work=[[BBC News Online]] |access-date=9 February 2010 |archive-date=2 January 2021 |archive-url=https://web.archive.org/web/20210102110412/http://news.bbc.co.uk/2/hi/uk_news/england/southern_counties/3456215.stm |url-status=live }}</ref>  In May 2003, sewage leaking from a pump operated by Thames Water leaked into the Stanford Brook, killing coarse fish in the Gatwick stream.<ref>{{cite web |url=https://www.telegraph.co.uk/news/uknews/1437261/Water-firms-abusing-sewage-law-loophole.html |title=Water firms 'abusing' sewage law loophole |first1=Rajeev |last1=Syal |first2=Graham |last2=Mole |date=27 July 2003 |work=[[The Daily Telegraph]] |access-date=5 January 2011 |archive-url=https://web.archive.org/web/20120416210020/http://www.telegraph.co.uk/news/uknews/1437261/Water-firms-abusing-sewage-law-loophole.html |archive-date=16 April 2012 |url-status=live }}</ref>

Water quality of the River Mole in 2019:
{| class="wikitable"
|-
! Section !! Ecological<br/>Status !! Chemical<br/>Status !! Overall<br/>Status !! Length !! Catchment !! Channel
|-
| {{waterqual_title |desc=Mole (Horley to Hersham) |asset= GB106039017621}}
| {{waterqual_mod}}
| {{waterqual_fail}}
| {{waterqual_mod}}
| {{convert| 60.133 |km|mi|abbr=on}}
| {{convert| 151.017 |km2|sqmi|abbr=on}}
| 
|-
| {{waterqual_title |desc=Mole (Hersham to R. Thames conf at East Molesey) |asset= GB106039017622}}
| {{waterqual_mod}}
| {{waterqual_fail}}
| {{waterqual_mod}}
| {{convert| 9.507 |km|mi|abbr=on}}
| {{convert| 21.803 |km2|sqmi|abbr=on}}
|  Heavily modified
|}