Deeping Fen is a low-lying area in the South Holland district of Lincolnshire, England, which covers approximately 47 square miles (120 km2).

His son, John Grundy, Jr., was another capable engineer, who was retained as a consultant after he resigned as full-time Surveyor of Works.

This plan was not implemented immediately, but two steam engines fitted with scoop wheels were installed at Pode Hole in 1823.

The work included making the Welland deeper and wider from Deeping St James to its outfall beyond Spalding, and the construction of side drains.

His plans were approved, and the Adventurers offered to give him land covering nearly 6,000 acres (2,400 ha) in payment for the work.

At high tide, water was penned in Cowbit Wash, between banks which were set well back from the main channel.

At low tide, the sluice gates were opened, and the flow scoured out silt from the river bed for some 3 miles (4.8 km) downstream.

[9] Perry was succeeded by John Grundy, Sr., who had arrived in the region in 1731 at the request of the Duke of Buccleuch, who wanted his estates surveyed.

In July 1737 Grundy and Humphry Smith set out their plans for the fen, and a bill was put before Parliament, to allow the Adventurers to raise the £15,000 estimated cost by taxes.

They oversaw a programme of repairs to the Deeping Bank, which ran for 12 miles (19 km) along the south-eastern edge of the fen, protecting it from the Welland.

The bed of the Glen had also been regraded and its banks raised by 1742, when Smith retired and Grundy took sole charge of the works.

He oversaw the job of making the Welland through Spalding deeper and wider, and suggested that the outfall of Vernatt's Drain should be moved 2.5 miles (4.0 km) downstream from its existing position.

[11] Hogard devised a scheme to cut a new channel from the junction of the Welland and the Glen to Wyberton, on the estuary of the River Witham below Boston.

The Adventurers asked Thomas Tofield for a second opinion, who suggested a shorter 5-mile (8.0 km) cut from Spalding to Fosdyke.

They requested help from Grundy, who proposed a 1.5-mile (2.4 km) cut to Fosdyke, and that the outfall of Vernatt's drain should be moved downstream as his father had suggested.

The first was an outfall at a lower level, which would involve hugh expense in its construction, and the second, favoured by Jessop and Rennie, was the provision of steam pumping engines at Pode Hole.

The larger one was manufactured by Butterley, was called the Holland engine, and drove a scoop wheel which was 28 feet (8.5 m) in diameter.

[17] Pinchbeck South Fen is a region covering 1,700 acres (690 ha) lying on the west side of Vernatt's Drain.

However, the charges levied by the trustees for this service rose dramatically, so that the South Fen residents decided to build their own pumping engine at Pode Hole in 1830.

A Fenton & Murray beam engine driving a 20-foot (6.1 m) scoop wheel was installed, at a cost of £3,000, which was considerably less than the charge the trustees wanted to make.

[18] Pinchbeck Marsh was also part of Deeping Fen, but following the failure of the work carried out under the 1801 Act to effectively drain the area, an act of Parliament was obtained in 1832 to create a separate district, called the Spalding and Pinchbeck District, or Blue Gowt, as water from the 6,000 acres (2,400 ha) feeds into the River Glen from the Blue Gowt Drain.