River Gipping
During 1791, when the Trustees were negotiating with John Rennie, they had asked him to assess an extension of the navigation from Stowmarket to the River Lark at Bury St Edmunds, but this was not pursued. With the navigation thriving, there were two proposals for canals from Ipswich to Eye, Suffolk in 1819. A meeting was held in January at Eye, which was chaired by Charles Cornwallis, 2nd Marquess Cornwallis. It considered two reports, one proposed by the civil engineer William Cubitt, which involved a tunnel through the hills at Mendlesham, with the estimated cost exceeding £100,000, and another, for a canal over the hills, costing £80,000. Both were thought to be too expensive to implement, but a third proposal emerged, for an extension from the River Gipping at Needham Market, which would follow the valley of a tributary through Creeting St Mary to Earl Stonham, where a basin would be built beside the turnpike road (now the A140 road). This would enable waggons to make a round trip from Eye in a single day, rather than the two days that a trip to Ipswich took. The scheme was estimated to cost £12,000, and shares in it were offered at the meeting. Although many were taken up, the scheme did not advance any further.
Gaoping
The hilly area around Gaoping is known as the Sheep's Head Mountains (), and it is this area that preserves the most concrete evidences of Yan's habitation there. A local temple to a female river spirit has been identified as portraying Yan's daughter Nüwa () - not to be confused with the goddess Nüwa () - since the Ming Dynasty. Ancient sources, such as the Guo Yu, record that Yan and his posterity flourished in the area around a river called the "Giang [Jiang] Water". The river is believed by scholars to be the Giang River of old is now called the Jiang River () or the Jiang Water (), and is located in Tunliu County, whence it flows east into the Zhang River.