Editing River Parrett (section)

===Hydrology and water quality===
Near the source at Chiselborough the typical level range for the depth of the river is {{convert|0.05|m}} to {{convert|0.63|m}} but has reached a maximum of {{convert|2.93|m}}.<ref>{{cite web|title=River Parrett at Chiselborough|url=http://apps.environment-agency.gov.uk/river-and-sea-levels/120716.aspx?stationId=3075|website=River and Sea Levels |publisher=Environment Agency |access-date=19 June 2015 |url-status=live |archive-url=https://web.archive.org/web/20150619203447/http://apps.environment-agency.gov.uk/river-and-sea-levels/120716.aspx?stationId=3075 |archive-date=19 June 2015}}</ref> The mean flow rate is {{convert|1.196|m3/s}}.<ref>{{cite web|title=52007 – Parrett at Chiselborough |url=http://www.ceh.ac.uk/data/nrfa/data/meanflow.html?52007 |publisher=Centre for Ecology and Hydrology |access-date=19 June 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150619195737/http://www.ceh.ac.uk/data/nrfa/data/meanflow.html?52007 |archive-date=19 June 2015}}</ref> By the time it reaches Gaw Bridge the normal level range is {{convert|0.23|m}} to {{convert|0.97|m}} and a highest reading of {{convert|3.84|m}}.<ref>{{cite web|title=River Parrett at Gaw Bridge|url=http://apps.environment-agency.gov.uk/river-and-sea-levels/120716.aspx?stationId=3072|website=River and Sea Levels |publisher=Environment Agency |access-date=19 June 2015 |url-status=live |archive-url=https://web.archive.org/web/20150619204640/http://apps.environment-agency.gov.uk/river-and-sea-levels/120716.aspx?stationId=3072 |archive-date=19 June 2015}}</ref> At West Quay in Bridgwater where the river is tidal the highest astronomical tide level is {{convert|8.63|m}} above [[ordnance datum]] (AOD).<ref>{{cite web|title=River Parrett (Tidal) at West Quay|url=http://apps.environment-agency.gov.uk/river-and-sea-levels/120716.aspx?stationId=3067|website=River and Sea Levels |publisher=Environment Agency |access-date=19 June 2015 |url-status=live |archive-url=https://web.archive.org/web/20150619204128/http://apps.environment-agency.gov.uk/river-and-sea-levels/120716.aspx?stationId=3067 |archive-date=19 June 2015}}</ref>

For the purpose of water quality measurement, the river is divided into five water body areas by the [[Environment Agency]]. In 2015, both the area from the source to Broad River around Crewkerne and the area from Broad River to Lopen Brook are rated good for chemical quality and moderate for ecological quality.<ref>{{cite web|title=Parrett&nbsp;– headwaters to Broad River|url=http://environment.data.gov.uk/catchment-planning/WaterBody/GB108052015260|website=Catchment Data Explorer|publisher=Environment Agency|access-date=19 June 2015}}</ref><ref>{{cite web|title=Parrett&nbsp;– Broad River to Lopen Bk|url=http://environment.data.gov.uk/catchment-planning/WaterBody/GB108052015321|website=Catchment Data Explorer|publisher=Environment Agency|access-date=19 June 2015}}</ref> The area from Lopen Brook to the River Isle, around Martock and South Petherton, is rated good for chemical quality, poor for ecological quality and poor overall.<ref>{{cite web|title=Parrett&nbsp;– Lopen Bk to R Isle|url=http://environment.data.gov.uk/catchment-planning/WaterBody/GB108052015360|website=Catchment Data Explorer|publisher=Environment Agency|access-date=19 June 2015}}</ref> From the River Isle to River Yeo around Muchelney, chemical quality is rated good, and ecology is rated moderate.<ref>{{cite web|title=Parrett&nbsp;– R Isle to R Yeo|url=http://environment.data.gov.uk/catchment-planning/WaterBody/GB108052015370|website=Catchment Data Explorer|publisher=Environment Agency|access-date=19 June 2015}}</ref> The section around Langport to the West Sedgemoor Drain continues to rate good for chemical quality and moderate for ecological quality,<ref>{{cite web|title=Parrett&nbsp;– R Yeo to West Sedgemoor Drain|url=http://environment.data.gov.uk/catchment-planning/WaterBody/GB108052015470|website=Catchment Data Explorer|publisher=Environment Agency|access-date=19 June 2015}}</ref> as does the final area leading to Bridgwater Bay.<ref>{{cite web|title=Parrett|url=http://environment.data.gov.uk/catchment-planning/WaterBody/GB540805210900|website=Catchment Data Explorer|publisher=Environment Agency|access-date=19 June 2015}}</ref>