<Tr> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <P> The River Alt is an urban river that flows across Merseyside in England . The river has suffered from heavy pollution from industry and sewage upstream and run - off from farmland in its lower reaches . It empties into the River Mersey, near to where the Mersey itself, flows into the Irish Sea . the river has benefited from clean - up schemes and a de-culverting process to improve its water quality and provide a better environment for wildlife . </P> <P> The Alt runs from Hag Plantation in Huyton at 125 ft (38 m), through Croxteth Park, roughly follows the M57 motorway south of Kirkby, then flows north of Aintree and south of Maghull . Historically in Lancashire, it then runs south of Formby and empties into the Irish Sea, near the edge of the River Mersey estuary at Hightown . </P> <P> The Alts upper waters deriving from small streams and, in particular, one arising at Hag Plantation in Huyton . This is the location of the primary source of the river and is also the Huyton Wetlands Site of Biological Interest (SBI). The Alt then flows at a low gradient across an alluvium plain in a northwesterly direction before turning southwards and emptying into the River Mersey at Hightown between Crosby and Formby . </P>

Where does the river alt start and end