Much of the water flowing in this surface portion of Mud Creek is not from its former or local watershed, rather it is diverted from the Forman and Bayview Avenue storm sewers located north east of the ravine, which drains the Upper Cudmore Creek watershed. The open section of Mud Creek runs 2.1km to the Don River, mostly adjacent to the Beltline Trail where it is buried for short stretches as it is repeatedly diverted to opposite sides of the trail before finally emerging through the Don Valley Brick Works. Moore Park Ravine begins just south of Moore Avenue and ends with the open space of the Don River valley. Adjoining Mont Pleasant Cemetery, the first portion of the ravine from Moore Avenue to Heath Street (c. 1890s Clarence Avenue) was known as "Spring Valley" and was marketed by the Toronto Belt Line Railway Company as such with the name also applied to the creek. The creek and the ravine is considered one of the best nature walks in Toronto. The creek enters into the Don River valley at the Don Valley Brick Works, where its flow bifurcates through or adjacent to the ponds, and then re-converges shortly before exiting into the Don River south of Bayview Avenue. The ponds serves to hold and provide biological filtration for the inflow from Mud Creek prior to discharge into the Don River, and is part of Toronto storm-water management strategy. Due to the geology and depth of the ravine, erosion and foresting work has been ongoing to preserve its integrity as well as the "Beltline Trail" that runs through it. A pivotal scene in Margaret Atwood's novel Cat's Eye was set in Mud Creek near the Heath Street footbridge, where the protagonist describes wading into it: