Editing River Welland (section)

==Geography==
The River Welland, with its tributaries, forms a river system with a catchment area of {{convert|609|sqmi|km2}}. Within this area, {{convert|257|mi|km}} of waterway are designated as "main river", and are therefore managed for flood control by the [[Environment Agency]] under the River Welland Catchment Flood Management Plan (CFMP).<ref>{{cite report |url=http://publications.environment-agency.gov.uk/pdf/GEAN1209BRIZ-e-e.pdf |title=River Welland Catchment Flood Management Plan |author=Environment Agency |date=December 2009 |access-date=26 May 2018 |archive-url=http://webarchive.nationalarchives.gov.uk/20100530161928/http://publications.environment-agency.gov.uk/pdf/GEAN1209BRIZ-e-e.pdf |archive-date=30 May 2010}}</ref> Of this total, the {{convert|14|mi|km}} below Spalding are tidal, and have sea walls to protect the adjacent land from flooding, while {{convert|56|mi|km}} are fresh water, but run through low-lying land, and are therefore embanked. Within the catchment area, {{convert|179|sqmi|km2}} are below sea level, and would be flooded without such defences.<ref name=unesco>{{cite web |url=http://portal.unesco.org/science/es/ev.php-URL_ID=3800&URL_DO=DO_PRINTPAGE&URL_SECTION=201.html |archive-url=https://archive.today/20130416015054/http://portal.unesco.org/science/es/ev.php-URL_ID=3800&URL_DO=DO_PRINTPAGE&URL_SECTION=201.html |url-status=dead |archive-date=16 April 2013 |title=Welland (UK) Operational HELP basin |publisher=UNESCO |access-date=17 March 2011}}</ref>

The basin runs in a broadly south-west to north-east direction, with an extension to the north around the West Glen and East Glen rivers. The underlying geology consists of [[Lias Group|Lias clays]] at the western end of the catchment, with [[Lincolnshire limestone]] in the centre, including the valleys of the Glen. The eastern third is mostly [[Alluvium|alluvial soils]], and it is this part that relies on artificial pumping to prevent flooding. Rainfall over the area varies between {{convert|26|and|30|in|mm}} per year, which is quite light, and because the land is efficiently drained during the winter months, there are few reserves, making the area prone to drought in the summer months.<ref name=unesco/>

For much of its length the Welland forms the county boundary between Northamptonshire and [[Leicestershire]] or [[Rutland]], and lower down between [[Lincolnshire]] and [[Cambridgeshire]].