909 Ty Gwyn Outfall Ynys, Harlech, Gwynedd Archaeological Assessment GAT Project No. 2159 Report No. 909 December, 2010 Ymddiriedolaeth Archaeolegol Gwynedd Gwynedd Archaeological Trust Craig Beuno, Ffordd y Garth, Bangor, Gwynedd, LL57 2RT Archaeological Assessment: Ty Gwyn Outfall, Ynys, Harlech Report No. 909 Prepared for Environment Agency December 2010 By Andrew Davidson Ymddiriedolaeth Archaeolegol Gwynedd Gwynedd Archaeological Trust Craig Beuno, Ffordd y Garth, Bangor, Gwynedd, LL57 2RT CONTENTS 1. Introduction 2. Aims and Specification 3. Methodology 4. Location and Topography 5. Historical and Archaeological Background 6. The Study Area 7. Impact and Recommendations 8. List of sources consulted LIST OF FIGURES Fig 1: Location of scheme Fig 2: Location of archaeological sites Fig 3: OS Second Edition 1900 Fig 4: Sketch by Allom. Mid-19th century Fig 5: Sketch by Turner. LIST OF PLATES Plate 1: Ty Gwyn from north Plate 2: Ty Gwyn from east Plate 3: Wooden posts north of Ty Gwyn Plate 4: Wooden posts north of Ty Gwyn Plate 5: Llechollwyn from east Plate 6: Steps at Clogwyn Melyn Plate 7: River channel looking west Plate 8: River channel looking east 1. INTRODUCTION Gwynedd Archaeological Trust was asked by the Environment Agency to provide an archaeological assessment in advance of proposed improvements to the outfall at Ty Gwyn, Ynys, Harlech. The outfall runs from the tidal gates at Ty Gwyn (at SH59973547) some 300m north into the Dwyryd estuary and then 500m west parallel to the coast, finishing at approximately SH59533588. The outfall lies within the intertidal zone throughout its length. 2. AIMS AND SPECIFICATION A detailed brief has not been prepared for this work. This design will follow the guidelines specified in Standard and Guidance for Archaeological Desk-based Assessment (Institute of Field Archaeologists, 1994, rev. 2004). The advice of the Development Control Archaeologist should be sought before recommendations are finalised. A desk-based assessment is defined as “a programme of assessment of the known or potential archaeological resource within a specified area or site on land, inter-tidal zone or underwater. It consists of a collation of existing written, graphic, photographic and electronic information in order to identify the likely character, extent, quality and worth of the known or potential archaeological resource in a local, regional, national or international context as appropriate” (Standard and Guidance for Archaeological Desk-based Assessment 1994, rev. 2004). The aims of the assessment are: to identify and record the cultural heritage within the defined study area; to evaluate the importance of what has been identified; to recommend ways in which impact upon the cultural heritage can be avoided or minimised. To comply fully with the aims expressed above it can be necessary to undertake a programme of Field Evaluation following the Desktop study and Field Visit. This is because some sites cannot be assessed by desktop or field visit alone, and additional fieldwork is therefore required. This typically takes the form of geophysical survey or trial excavation, although measured survey is also a possible option. A full programme of assessment and evaluation may therefore consist of: Desktop study Field walkover Initial report Field evaluation Draft report Final report This assessment includes the first three phases only, and recommendations will be made for any field evaluation required. 3. METHODOLOGY 3.1 Desk top study The desktop study comprised the consultation of maps, documents, computer records, written records and reference works, which form part of the Historic Environment Record (HER), located at Gwynedd Archaeological Trust (GAT), Bangor. The archives held by the Meirionnydd Record Office, Dolgellau and Bangor University were also consulted. Information about listed buildings was consulted by means of the CARN (Core Archaeological Index), which is the online index of the Royal Commission on Ancient and Historic Monuments, Wales. Relevant aerial photographs from the collection at RCAHM, Wales were examined. 1 3.2 Field Search The course of the proposed outfall and surrounding area was visited in November 2010. Notes were taken, and a photographic record was made of the area and features. 3.3 Report The available information was synthesised to give a summary of the archaeological and historic background and of the assessment and recommendations, as set out below. The separate features, their evaluation and recommendations are listed separately, and a summary of the overall assessment of the area is given at the end. The criteria used for assessing the value of features was based upon those used by the Secretary of State for Wales when considering sites for protection as scheduled ancient monuments, as set out in the Welsh Office circular 60/96. 4. LOCATION AND TOPOGRAPHY Ty Gwyn is the name given to a former harbour and dockside warehouse which lie on the west side of a small estuary on the north side of Morfa Harlech. This small estuary carries both the Afon Glyn and Harlech drains (a group of water courses which drain the low lying fields of the Morfa) which flow into the much larger estuary of the Afon Dwyryd. North of Ty Gwyn, and still lying within the Dwyryd estuary is a small island called Ynys Giftan. On the north side of the Dwyryd estuary lies Portmeirion (formerly a small harbour called Aber Ia), whilst beyond the end of the Penrhyndeudraeth peninsula can be seen Porthmadog and the south coast of the Llyn peninsula. The Dwyryd estuary is crossed some 3 Km north-east of Ty Gwyn by Pont Briwet road and rail bridge. Below Pont Briwet the estuary is usually referred to as Traeth Bach, whereas above the bridge it becomes Afon Dwyryd. The estuary is tidal, however, as far as Maentorog. The development of the estuary at Ty Gwyn is closely related to the development of Morfa Harlech. This is one of two expanses of Morfa (the other being Morfa Dyffryn) which lie at the north end of Cardigan Bay, and form the coast edge between the Dwyryd estuary in the north and the Mawddach estuary to the south. Morfa Harlech is triangular in shape, and measures some 6Km north to south and 5Km east to west along the north edge. The west side of the triangle is formed by the coast edge, the east side by the rising edge of the Harlech Dome (which marks the original shoreline), and the north side by the Dwyryd estuary. The castle and borough of Harlech lie at the south point of the triangle. The Morfa is, in general, very low lying, most of it below 10m OD, with the exception of small areas of higher ground which would have been former islands. The largest of these is Ynys on the north edge of the Morfa, and on which stands the church of Llanfihangel y Traethau.Ty Gwyn lies on the east side of Ynys, and on the west side of the Afon Glyn estuary. Lasynys, birthplace of the writer Ellis Wynne, is smaller and located on the east edge of the Morfa. Also lying above the floor of the Morfa are the sand dunes which now divide the Morfa from the sea along the west coast. The geomorphological model argued by Steers (1964, 132-6) and more recently by May (2003, 449- 53) is that the area that was to become the Morfa originally lay within the tidal estuary of the Dwyryd. The original coastline, or south-east edge of the estuary, is marked by the rising Cambrian rocks of the Harlech Dome, whilst Ynys was an island within the mouth of the estuary. The remaining area of the Morfa lay under water, or within tidal waters. A shingle ridge developed north from Harlech, around which sand dunes grew. The date of this is uncertain, but development of the ridge is likely to have started in prehistoric times. Between the shingle ridge and the original shoreline an area of salt marsh developed. This was fed by tidal ingress either side of Ynys. When the castle was built in the late 13th century tidal waters or channels through the salt marsh allowed access to the water gate. This access may have been around the north end of the developing shingle ridge, which in turn would have sheltered the castle water gate from the sea. As the shingle ridge, and in particular the sand dunes developed, so access to the castle by boat became impossible. In his conclusion, May (ibid, 453) states ‘Morfa Harlech is the result of several phases of as yet undated spit growth, and the progressive sedimentation and land-claim of the area between the beach and the former rocky sea cliff upon which Harlech Castle stands’. 2 The west side of the Morfa, inland of the sand dunes, remained an area of salt marsh, known as Harlech Marsh, until the Enclosure Act of 1806, when defensive sea banks were built at Ty Gwyn to the west of Ynys to control tidal waters, and the former marsh was sub-divided into large square or rectangular fields. A central north-south ridge within the Morfa had, however, already been drained and enclosed as early as the 15th century, and the strips of this field system can still be seen. To the east of this field system, between the fields and the original coastline, lies wetter ground, now better drained, but in the 16th century it was described as a turbary (for peat cutting). The general drainage of the Morfa flows from south-west to north-east, and whilst the Morfa is criss- crossed by a grid of small drains, three principal drains cross the area and merge before discharging into the Afon Dwyryd alongside Afon Glyn. It is probable that these form a critical part of the medieval enclosure of the Morfa.