Anglo-Saxon coastal fish weir at Collins Creek, River Blackwater (EHER 13815)

A complex series of timber alignments, measuring at least 3.0 km by 0.7 km overall, was recorded at Collins Creek in the Blackwater estuary. Three sets of radiocarbon dates from timbers in different parts of the alignments are all within the Saxon period. These structures are interpreted as fish weirs; associated with them are stretches of wattling, which are thought to have facilitated access for collecting the fish, and for carrying out repairs.

August 1991. Field survey. The site consists of many thousands of wooden post 100-150mm in diameter set in parallel lines. Between the matrix of posts is a matrix of smaller timber giving the impression of brushwood or hurdle fencing laid flat. The main rows of timbers are orientated east-west and run roughly parallel to the low water mark. In places the shingle banking has been thrown up over the line of posts and they disappear, only to reappear on the same line where there is less deposition of shingle. The lines appear to cross the inlets of the creeks. The posts run for approximately 1 mile in an east-west direction. Part way along the east-west row is an intersection with another pair of parallel rows of stakes of multiple formation, running some half mile from the intersection towards the north-west. In the south-easterly direction the posts are only visible for a few metres before disappearing under the main river. The main east-west run consists of multiple posts set at 30-50cm centres and 3.8m apart. The 3.8m gap appears to contain brushwood/hurdle like material. 11 metres to the north of the rows of multiple posts is another row of single posts 75-100mm in diameter and approx. 30cm apart. There is some evidence of a further row of similar spacing and diameter to the south, but much of this portion of the site does not uncover even at low tide. In all cases some 100-150mm of post end is exposed above the surface of the mud, with the smaller infill lying on the surface where it is exposed to tidal action. Pieces of worked wood have been found: a mortise and tenon in situ; a section of cleft oak with visible tooling marks. <1> August 1991. Field visit. In August 1991 the site was recorded by aerial photography which revealed the large scale of the structures. Field visits by members of the Essex County Council (ECC) Archaeology Section and other specialists followed. Two samples collected for radiocarbon dating gave dates of 640-675 AD and 882-957 AD. Current thought favours their interpretation as fish weirs. <2> - <10> 1992-1993. English Heritage research project: field survey. ECC Archaeology section are currently recording the site (with funding by English Heritage).<3> Radiocarbon dates from three samples gave a date range of 664-797AD. <11> The timber alignments at Collins Creek are interpreted as a series of Saxon fish weirs, measuring overall at least 3.0 km by 0.7 km. As such they are probably one of the largest, if not the largest, known from south-east England. It is worth pointing out that at least one other interpretation of these structures has been considered, namely that it was a wooden revetment protecting and stabilising a small island, now lost through erosion, in the middle of the Blackwater estuary. In order to test this possibility, Peter Murphy carried out an auger survey across the sediments into which the southern east-west timber alignment had been driven. The results of the auger survey rather confirm the interpretation of the structure as a fish weir (or weirs). However, given the size of the site, it is inherently unlikely that these timbers are all of a single phase. Other fish weirs in the inter-tidal zone along the Essex coast, and further afield, tend to be simple V-shapes, with the apex of the V pointing out to sea, so that on the ebb tide, fish are channelled towards the point of the V, where they are collected. In other Essex examples, the sides of the V are typically anything between 80 and 390 m long. Examination of the Collins Creek plan (produced by the survey work of this project) shows a number of potential V-shapes, along the main east-west alignment, and also in the northern central part of the mud bank. It is unlikely that all of these were in operation simultaneously, as the radiocarbon results are statistically significantly different at 95% confidence. The five radiocarbon dates indicate that the construction (or repair) of these structures spanned several centuries. During that time, there may have been piecemeal repair, minor modification or radical alteration in the lay-out. <12> See <12> and <13> for mor details of the research project. 1997. Aerial photography and radiocarbon dating. See <14>. 2010. Field survey. See <15>. See aerial photographs <16> - <23>. See cropmark plot <24>.