In 2011 John C. Lewthwaite published two articles which examined some of the technical and engineering questions concerning the canal.
THE OLD SLUICE AT HILL HEAD HARBOUR
Titchfield Haven was shut out at the costs of the 3rd Earl of Southampton on 23 June 1611 according the Parish Register of that year. As part of this work it is assumed that a sluice was constructed under the shingle bank to permit the river to continue to run out to the sea. This is shown in a map (HRO 1M46/1), but which is not dated, a detail from which is shown on page 70 (East is uppermost).
The shingle bank which now forms the western side of Hill Head harbour is shown to have an “old sluice” close to its mid-point and a new sluice closer to the shore. The new sluice has been renewed and is currently used to permit the river to run out at low tide. The old sluice has been closed off at its harbour side. Both these sluices can be seen today.
The old sluice was last used in the late 1940’s whilst the gates on the new sluice were replaced over a period of several months. The old sluice was subsequently blocked on the harbour side.
As part of general research on the local area a group has been formed to investigate the history. The GATHER (Group Acquiring Titchfield Haven early Records) group was formed in October 2007 and one of its earliest studies has been to examine the old sluice.
From the marsh side the old sluice is approached by a water filled gully about 2m wide which then enters a tunnel under the road over the old shingle bank. This is believed to be the gully with the left-angled leg shown on the closure map (Fig 1). The water in the gully was only a few inches deep but covered about 3 ft of mud and silt. There were a number of old planks close to the entrance which were probably left behind when the sluice was damaged in about 1980.
A small dinghy was used to get into the sluice which was examined on 15 November 2007. Since the sluice was built to Imperial units these are used to define its dimensions, although metric equivalents are given in [brackets].
The sluice is 92in [2340mm ] wide. The lower part (culvert) is built using dressed stone about 10 in [250mm ] wide which appeared to be old (maybe 1600’ s). Depth soundings in the culvert indicated that the water was about 36in [915mm ] deep, although the lower 30in [75mm ] was thick mud partly filled with debris (old planks and stones). The bottom appeared to be level and hard, suggesting it was made of stone.
The top arch of the sluice is built using bricks (8¾ in long, 4in wide & 2in deep). These look thin compared to modern bricks and may be as old as the stones. The cement appears to be original and not to have been refaced in recent times. The outer edge of the b rick arch is in a poor condition and there is a danger that a further collapse may occur. The bank around the arch is covered in hedging and bushes which line the road above. The road is only about 30in [760mm ] above the top of the arch.
The water level in the sluice on the day it was examined was about 6 in [150mm ] below OS datum. This was assessed by measuring the water height at the new sluice against an OS Benchmark on the bridge. The old sluice is connected to the river, although the gully is overgrown with reed beds. The water level in the river changes slightly with rainfall amounts, although on the day in question it was judged to be at a typical height.
The harbour end of the tunnel has been filled with concrete. It is understood that this was done in about 1985 when work-men digging a trench for a pipe from Meon shore along the road broke through into the sluice. As an expedient the hole and tunnel below were filled and this will prevent the sluice being used again.
As mentioned, the closure map (Fig. 1) is not dated. It shows at the top (south) that a breach occurred in the sea bank at some time. It is surmised that after a prolonged rainy period the water in the river Meon rose to a level that the old sluice was unable to discharge adequately. Correspondingly, the high water level forced the breach in the sea bank. It was therefore necessary to construct a larger new sluice. The earliest record of such activities is in a letter by Clement Walcott (HRO 5M 53/1115) in 1743, in which he refers to the need to locally dig clay for repairs to Hill Head. A map prepared when the estate was sold to the Delme’s in 1753 (HRO 21M53) indicates that there was not a breach in the sea bank and that both sluices were operating. This is confirmed in a subsequent map by Archer & Pitts dated 1774 (in British Library), but apparently the old sluice was not in operation in 1837 as indicated by the Titchfield Parish Tithe map.
It is therefore apparent that the old sluice predated 1743 and it is very likely that it was built at the same time that the estuary was closed in 1611. That is, that the stonework is about 400 years old. The brick arch may have been repaired later but a sluice covering a height of 100in [2.5m] above the river level would have been necessary to prevent overtopping by high spring tides on the harbour side.
THE SEA LOCK
At the southern end of the Titchfield Canal there is supposedly a sea lock which was used to permit barges to enter the canal from waiting ships moored in the entrance from the sea.
The view today is shown by this photograph taken from the canal side with the seaward side beyond.
The water level on the canal side is controlled upstream by a sluice. The seaward side is very overgrown and closed to the sea.
The three-arched bridge is a later addition and covers where the lock was apparently installed. A local information board on the east side reports that the area in Grade II listed and was restored in 1994. It describes the old lock as a pair of simple staunch gates which could only be opened when the water level on both sides was the same. The area was examined in June 2008. The width where the bridge is fitted is 16 ft (5.0m). The water depth was 3 ft (0.9m ) deep and this is relatively constant since there are drains under the road on the seaward side which empty in to the marsh. The bottom was probed from the bridge and the side banks and found to be hard and level (stoned lined ?). Remains of iron-work type fittings can still be discerned on the seaward side, indicated by the line.
It is not clear whether the lock gates were designed to swing inwards from the sea or outwards from the canal. Nor it is clear as to how the gates could be secured against a head of water from either side. An old Ordnance Survey map (dated 1941) shows a Bench Mark on the road over bridge at a height of 7.53ft (2.3m).
Since the road over the bridge is 3.3ft (1.0m ) above the water, this indicates that the water level is currently about 4.3ft (1.3m) above the OS datum. The datum is the mean level of tides which locally range a b out + /- 5 .9 ft (9.1m) on Neaps to +/- 7.9ft. (2.4m) on Spring tides.These relevant heights are shown below assuming that the sea lock is closed: If the entrance were still open to the sea, the water on the seaward side of the lock on Spring tides with a height of 7.9ft (2.4m) relative to the OS datum, would tend to flood over the bridge and lock sides to a depth of about 0.3ft (0.1 m)! However, data from the Inter-government Panel for Climate Change suggests that sea levels were about l ft lower 300 to 400 years ago. It should also be noted that the range of Spring tides in those years was little different from today. So it may be concluded that the maximum height of tide probably did not quite reach the top of the lock sides all those years ago.
Observations also indicates that the height of the road leading from the lock to Meon Shore is about 0.6ft lower than that over the bridge and hence on Spring tides 300 to 400 years ago, the maximum height of the tide would have been very close to the present road level. It might therefore be concluded that there must have been a raised bank where the road now runs.
We know that the lock was open to the sea from the “ closure map” (HRO 1M 46/ 1- which is not dated), a section of which is shown on page 70 (East is uppermost). The waterway is called the “ New River”, the bridge is clearly marked by the words “ Meon bridge” and the road is entitled “ sea bank called Hill Head”. It can be seen that the word “ sluice” is shown on this map, rather than lock.
If there had been a simple staunch lock then it would have had to be able to withstand a head of water of about 3.3 ft (1.0m) either on the canal side at low tide, or a similar height from the seaward side on Spring tides. The load imposed on a 16ft (5.0m) wide structure has been calculated to be about 2.5 tons force! It would seem unlikely that the ironwork hinges would have withstood such loads.
The concept of opening the staunch gate lock only when the water levels were the same, is hardly practical since the tide would have been rising steadily relative to the canal level, leaving only a few minutes of operation. with any difference in water levels, a significant current would develop making it very difficult to close the gates.
Furthermore, if the gates were not closed on Spring tides the water level in the canal would have been raised by about 3.3ft (1.0m) all the way up to Titchfield, probably flooding over adjacent fields. Since this in flow was from the sea, this would have contaminated the area with salt water.
It is therefore concluded that a single “staunch” lock would be impractical at this point. A more controllable structure would have been constructed such as a sluice, as indicated on the “closure” map, which could be partly opened to allow water to flow out of the canal as desired at low tide. Such an arrangement would of course preclude the passage of barges from the sea into the canal.
It might be postulated that ships could be moored alongside on the seaward side of the sluice and similarly barges on the canal side, with goods being transported across by cart. However, there was a well defined track from the sea lock to Titchfield (as shown on the 1610 map), so why not transport such goods directly from the sea lock by road? In any case, such goods would have had to have been off-loaded from the barges at Titchfield and distributed by cart – so what advantage did the canal offer? And there are no obvious landing quays on either side of the lock.
It has therefore been concluded, that there wasn’t a simple staunch lock at this location since the concept is impractical mainly because of water height differences. There was almost certainly a sluice as indicated on the “ closure” map. Such a sluice would have prevented craft from entering the canal. Small ships could have used the new sea entrance and distributed their goods by road. Perhaps the canal was simply a drainage/irrigation ditch.