To the Honourable the COMMONS of ENGLAND, in Parliament Assembled.  
A Proposal for Preventing the farther decay of our Harbours: Humbly Offered, by Robert Colepepyr, Gent.  
SINCE the Prosperity and Safety of this Island seems to be owing (next to the Providence of God) to the greatness of our Trade and Shipping. And since some of our Harbours are grown much worse, therefore it may seem fit to examine the cause thereof, the better to preserve them from further decay, and also to keep such Harbour's good as yet remain so; and since the same decay proceeds from Sand that doth settle and remain on our Bars and in our Bays, therefore I shall endeavour to show these two things. First, from what Cause those Sands do settle and remain. And Secondly, propose a way to prevent further increase of such Sands: Yet without Charge. And for proof of each of these General Heads, I will offer only such Observations and Reasons as are confirmed by Experience.  
First, I apprehend that those Sands are brought from without by Storms, and from within by Land-floods, and remain there for want of a large Basin or Indraught; for such increase of water would strengthen the influx and efflux, and not suffer any such Sand to remain.  
And first touching the settlement of Sea Sand. The Land that makes the mouth of the Bay or Channel, breaks the force of the water, and gives the Sand a more quiet place to settle in, than it had in more open parts of the Sea, and those parts are more quiet when the Ebbs issue out against Storms, than when Storms find the Tides flowing up the Channel; and in such Ebbs all the Sands are fenced out on the Bar, and in the Bay, and part of them cannot come into the Channel as they do in Tide-times; and if all influx and efflux were constantly so stopped, than a Bar in any Channels mouth would soon be raised, and grow level with the Sand and Beach lying on the Shores thereof. Therefore your Navigation requires influx and efflux that are great as well as constant.  
I confess the influx and efflux of Tides and Ebbs do keep some Sand from settling, and also remove other Sand after the same hath settled. But yet since the Sea-Charts show more Sand-banks in Bays and Channels mouths than are elsewhere found. Therefore the Land that makes them Bays, seems to be the cause of the Sea Sands settling therein.  
Secondly, I believe Sands may settle and remain on Barrs, from the great disproportion in breadth between that part of a Channel where a Bar lies, and the upper adjoining part of the same Channel; for the Ebbs have strength in the narrow part, and do thence remove such Sand as Land-waters or Tides and Storms cause there to settle, but cannot carry it all out beyond the Bar part of the Channel. First because there an over breadth doth weaken the Ebbs. Secondly, because the Sea is most apt to leave Sand on the Bar, and this Barr-sand obstructs the Channel-sand, and thereby augments the Bar, which will thus grow higher, till want of depth in the out fall brings the water to a rapidity (notwithstanding overbreadth) and gives it strength to remove all that shall afterwards settle on the Barr.  
And touching the weakness of influx and efflux to remove Sand, I apprehend the same may come from two Causes within the Barr. First, from checking the Land-waters in their passage out; and Secondly, from lessening of that Indraught or Bason the Sea hath within the Barr.  
First, to show this check given to Land-waters; I say the same is too often made by a Dam cross a Channel, with Sluices therein; yet this stop is intended only to keep Salt-water out of Land, and give passage to the fresh water. But these stops always do damage to Barrs and Bays. For in whatsoever part of the Channel this stop lies, the same detains Land-floods, and makes them pass out with less rapidity, and thereby abates their service to the Bar and Bay. For if you force water to pass through one foot square, that aught to have two, than you must give that water time to balance that restraint.  
And, Secondly, the Seas Indraught may be lessened by these two following ways. First, by the said Sluce-stop; for when the Tides reach this stop whilst they are flowing in over the Bar, than the stop doth this farther damage; for than it lessens the Indraught, and abates water (viz.) so much as would flow in beyond that obstructing part of the Channel, before the Tides ebb on the Bar, and this is the better part of the indraught, because the water that flows farthest in, returns latest over the Bar, and then the ebbs have the greatest rapidity.  
Secondly, these Indraughts are sometimes made less by Imbankments of Green-salts from the sides of a Channel. That is, when those Salts were drowned by high Spring-Tides, before those Tides did ebb on the Barr. But when the Salt you would imbank lies dry, when those Tides are ebbing on the Bar, than you may imbank that Salt without prejudice, for the Sea will not send in one Tunn of water the less for such Imbankments; and these Works in this place, and also higher up, will contract the water, and deepen the Channel; and the Thames with some other Channels have received depth from these Imbankments; therefore I think this Rule for Imbankments will hold good in any Channel, however the Tides flow as to distance from the Sea. And if Green-salts are found in a Bay, the same may be Imbanked with benefit, both to Navigation, and the Imbanker.  
'Tis generally concluded, that all Green-salts on the sides of Navigable Rivers, come from overbreadth (viz.) in the parts of the River where the same are found; and adjoining Land-Pearagers believe that all such Salts may be imbanked, and that Navigation will receive no detriment thereby.  
Touching the lower and Sea Indraught, part of a Channel that hath Green-salts. These parts I confess are too wide for their common Freshes and low Tides, as well as higher parts of the Channel, and by that means they lie dry sometimes, and bear Greene's, and Imbankments here will deepen a Channel as well as those made higher up; but the Channels in those lower parts are not too wide for Land-Floods, when the same meet pretty high Tides; nor are they ever too wide for the Spring-Tides, and to receive water from the Sea to scour Barrs and Bays.  
Tho' Imbankments out of these Sea Indraughts have been thought beneficial to Navigation, as well by the Government, who have Entitled, Permitted or Encouraged Men therein, as by those Men of Skill in such Works that advised the same. Yet I fear most of your Barrs and Bays have been rendered more unsafe by those Works. And if Patentees, and Land-Peeragers remain permitted to lessen your Indraughts by such Imbankments, whilst yet your Bays and Channels mouths retain their old breadth, and so require the same influx and efflux to keep them to their depth, than I apprehend your Barrs and Bays may have an increase of Sand, and that in proportion to the abatement of water made by such Imbankments.  
And I presume the damage these Imbankments will do to Barrs and Bays, is far more considerable than the benefit of deepning your indraught Channels, because good entrances into Harbours, tend most to the increase and preservation of Seamen and Merchandise. And when a Ship finds sufficient water at a good distance from the Sea, than she can hardly want till she comes to the Bar or Bay. But if such want of Water be found, than smaller Craft may Navigate in the Channels.  
I believe the Salt Indraughts do carry more Sand from Barrs and Bays than Land-waters, for these two Reasons. First, because the Land-waters bear but a small proportion with the Salt. And secondly, because the Tides of flood run strongest, and the Sands that lie firm and close during the Ebbs, are yet by the flowing waters made very lose and hollow; wherefore I think flowing Waters do most stir the Sand on the Barrs and in the Bays, and leaves it in motion to pass out to Sea in the Ebbs. And thus I hope I have shown that the imbankments of those Indraughts do abate the influx and efflux of your Water, and increase your Sands. Yet to make this point more plain, I pray leave to cite the four following Precedents.  
First, That many years since, a River called the Rother did pass through Rumney-Marsh in Kent, and near its issuing into the Sea, anciently made a Haven and Bay; but the Sea laid more Sand in the mouth of this Haven, than its indraught of salt Water and fresh could remove; and thereby shutting out the salt Water, and keeping the fresh in, it caused the latter to swell back in its own Channel, about six Mile, and there the fresh Water broke over its bounds, and went no more through Rumney-Marsh.  
There are many thousand Acres of imbanked Land under high-water mark in that Marsh, and lying on the sides of that Channel and Haven, and whilst un-imbanked, the flowing water must drown the same before it ebbed in the Haven. Therefore before Imbankments, those Lands were a large Indraught or Bason to that Haven and Bay. And if those Lands were imbanked from the Rother's Channel and Haven before they were so choked up, than we have good reason to believe those Imbankments choked up the same.  
And that those Imbankments did precede that Sand-stop, seems clear from the two following Causes. First, For that in an ancient Map of Rumny-Marsh the Haven is plotted, and in this plot are these words (The old decayed Haven of Rumney now swerved up, and the walls broken and decayed) and not Man would Imbank Land from a Haven, after 'twas left both by salt and fresh water. I can direct to the Original Map, or show a Copy thereof.  
But least the Authority of that Map should be questioned. I will secondly offer an argument from the natural tendency of Water (viz.) That the lower end of that Channel was more pressed with fresh water after that stop, than the parts six Miles higher could be; and all bounds of that Channel were equally strong, if the Lands were not imbanked. Therefore if no Banks had been in the way, save that in the Havens month, than the Freshes had swelled out at the lower end of their Channel, and there made a new Out-fall by the old one. Yet so it did not happen; but the Sea-barr and Channels-banks seem to force this water back, till it found a low or weak part of the Bank.  
I have an old Original Map showing the upper end of the Rother, and down to its falling into Rumny-Marsh. And in the same, Information is given, where nine Heads of several Rivers rise, and that they all served Mills, or Iron-Works, and after fall into the Rother. Hereby this Honourable House may see, that much Land-water must pass through that Channel into the Sea, from whence with the vast Indraught this Haven had, 'tis probable it might be a Royal Port. Yet these Rivers make but a very small fresh water in Summer, and such as might easily be overcome, and stopped in by Sand in Summer Storms; for the Haven must be very much too wide for its Indraught, after Rumny-Marsh was Imbanked. Thus much on this first Precedent, which I hope is well proved.  
Secondly, After the destruction of Rumny Haven the River Rother did pass through Rye Harbour in Sussex, and in 1623. the then Commissioners of Sewers for the Rother did make a Dam cross that River with Sluices therein to let out the fresh Water, and keep out the Salt; and this stop lying but six or seven Miles from the Sea, therefore the same did damnify the Harbour and Bay of Rye, as well by abatement of Efflux of Land Waters, as by lessening the Seas indraught, and these Sluices also caused so much Sullage to rest without them, that several Thousand Acres of Land within were thereby drowned with fresh Water.  
In 1635. 2000 Acres of Marsh (lying below that stop) were laid open to the Sea, and used as an Indraught or Bason to scour the Land drain; and this Indraught so far mended the Influx and Efflux, That soon after a Ship of 700 Tuns did ride at low water in Rye Harbour: But some Years since this Indraught and some green Salts began to be imbanked, and as the Seas Indraught was lessening by many imbankments, the Harbour and Bay did decay gradually and visibly, as those imbankments were brought to Perfection; insomuch that in the place where the Ship did ride at low Water, there the Sands now lie dry till half Flood; yet 'tis well known Rye was the best Tide-Harbour between the Downs and Portsmouth, into which good Ships could come from half Flood to half Ebb, but now that Coast affords no shelter to Ships of Burden: To prove the Stop made in 1623. and the Indraught in 1635 with their Consequences above Rye Harbour, for Vouchers I can direct to Records of Sewers, and for the Ships riding in Rye Harbour, with the after abatement of Water there, I have the copy of a Certificate under the Seal of that Corporation, and can inform where the Original may be seen.  
I believe the Harbour and Bay of Rye have lost three parts in four of their Indraught in manner as before, therefore the want of Influx and Efflux may well cause Sand to stay there, and make them decay more visibly and faster than most other Harbours and Bays; and although in some Bays the mischief done by Imbankments may not yet be perceived, yet the same leiseurly abatements of Water there may have an ill Consequence on this Kingdom, by obliging it to Ships that draw less Water, while neighbouring Nations build larger Ships of War: And so much on this second Precedent.  
Thirdly, Lest the Service myself and other Men allow to Imbankments in the parts wherever they are made should be ill applied, and brought as an Argument to clear Imbankments from all Damage in general, and thereby charge Storms as well with the cause of the Sands remaining, as with its first settlement, I will therefore pray this Honourable House to remember, that a few Years since the Thames made a narrow Breach in the Bank of Westthorock Marsh in Essex, and there drowned about 900 Acres of Land, and the Water by means of that narrow Passage in and out, was put into a great Rapidity, and thereby deepened its Entrance so much, that the Water was there near twenty foot deep at low Ebb, and the same Strength and Radity of Water so far continued after its Entrance, that the same cut a Channel near a Mile long in that Marsh, and this Channel bore a Depth in proportion to the mouth of it.  
This Channel was preserved deep by the Influx and Efflux of that 900 Acres of shallow Water, and the same remained an indraught, and scoured that Channel some Years; but 700 Acres of those Lands have been imbanked from the sides of that Channel, yet the Channel's Mouth retains its first Breadth; therefore the Influx and Efflux are abated in proportion to those Imbankments, and thereby much Sullage doth now remain in this Channel by lessening the Influx and Efflux.  
Since the last mentioned Channel or Water-fret is a good parallel with Rye Harbour, as well in holding Depth sufficient for Shipping whilst their Indraughts remained, as by increase of Sullage and becoming shallow as their Lands were imbanked; and since Rumny Haven was not destroyed till the Seas Indraught was taken from it, and since Westthorock Channel could have no Sullage driven into it by Storms, the same must be filled up by Imbankments, therefore all these decreases in Depth seem to come from Imbankments; and indeed we have little ground to think Storms without Imbankments will injure any of our Navigations, unless we can believe such Storms happened since our Imbankments as never came before: And this Honourable House may conclude that Kinsail would soon be rendered like Rumny, were not the Sand settles there removed by Influx and Efflux.  
The before Imbankments happening within my knowledge, or being so capable of proof as afore, I therefore contented myself with certifying the same, and have not enquired after other Damages of this kind, save only the decay of Lin Harbour, and I conclude this Honourable House may be assured that Denver Sluice lying in the River Ouse doth retard the Land Floods in their Passage through Lynn Harbour, and that by such abatement of Rapidity the more Sand stays there, and if that Sluice doth stop the flowing Tides before they ebb in that Harbour, than it lessens the Indraught, and abates the Influx and Efflux, and thereby also causeth more Sand to remain. So in the first, if not in both these ways of Damage, this Harbour becomes a fourth Precedent.  
These Imbankments of green Salts always make adjoining Slubbs and Water frets to hold shallower Water, if not to become green Salts; so the cutting shallow Water off from the Indraught makes other Water that was deepeer to become shallow: And thus by degrees Rye indraught was imbanked, and that Harbour and Bay made shallow, and in the same manor the indraught of any other Harbour may be imbanked, and no good Harbours left to Posterity. Therefore I hope this may show what imbankments will do, especially when a Channel's Mouth is left to the old Breadth. And hereby I hope I have proved my first general Head.  
Some Gentlemen are entitled to Salts by Patent, and others are entitled or permitted to imbank them as Land Pearagers; but the Government always presumes they cannot damnify the Navigation, and sometimes provides against it: Yet when Gentlemen have annexed these Lands to their Estates under Sales and Settlements, than I believe this Honourable House will always be tender, and not ruin Families by drowning of these Lands, and to buy them out may be very expensive; yet one of them may become necessary for the restroing of indraughts to their Ports.  
Workmen are much improved in Imbankments of late Years, for they imbank near the Sea, where the Income was formerly thought too little for the Risque and Charge: Therefore they may now do more of this Damage than was heretofore done in longer time. Wherefore if this Honourable House believes the Navigations in the said danger, than a Prohibition against any other Imbankments in the Seas Indraughts may preserve the Navigations from growing worse than they now are, and without Charge, and the same seems good Proof of my second general Head.  
And I believe the Bars that now hinder Navigation may be mended, if their ends at any time lie dry, for if the sand which Storms lay there, can be kept from washing away, than the Current (by abatement in Breadth) will be more rapid and deepen such Bars; and this Informant believes he can keep the Sand from washing off from the ends of a Bar, and that without any kind of Wood, or much Expense; which Experiment he is willing to impart at large to any Member of this Honourable House, or any Person from the Ports concerned, and will wait on them to that end, on a Note to be left at the Grocers over against the South Porch of St. Paul's Church: But I forbear herein to give this Honourable House any Particulars on this Head: First, because I presume the Charge will be thought private; and, Secondly, because I have no ample Precedents for this Work.  
FINIS.