Tidal Modelling - Detailed Tidal Range Model: Functional Summary and Testing Report

Abstract:

Launched in October 2011 this project involved Black & Veatch, in collaboration with HR Wallingford and the University of Edinburgh to develop a model of the UK Continental Shelf and North European Waters, 100 times more accurate than existing marine data. This has been used to assess the tidal energy potential around the UK (tidal range and tidal streams), to inform the design of energy harnessing schemes, to assess their interactions, and to evaluate their impact on European coasts. It can also be used to renew and inform flood defences, coastal erosion and aggregate extraction. Now completed, the project has been launched to market under the brand of SMARTtide. This is available to the marine industry under licence from HR Wallingford.

This report forms part of the D09 deliverables, which comprise the Detailed Tidal Range Model(DTRM) itself, and supporting documentation – Function Summary and Testing report. It describes the functional testing of the Detailed Tidal Range Model (DTRM). The Bristol Channel was selected on the basis that it provides an array of barrage and lagoon options from smallest (Oxwich and Morte Bays) up to one of the largest options (the Severn Outer barrage). In addition, the Bristol Channel contains some of the most economically attractive tidal range sites in the UK, and is relatively well understood in terms of hydrodynamics.

The DTRM extends to the mouth of the Bristol Channel, with a resolution of 50m at areas of interest and this resolution then grows at a rate of 8% up to the DCSM resolution at the interface. The DTRM operates in accord with tidal levels observed (and resynthesised) at Hinkley Point and Avonmouth. The DTRM slightly under predicts energy yield for the Severn Cardiff-Weston in ebb only mode in comparison to the range of results presented from DECC SEA Options Definition report. The reason for this is likely to be the less detailed bathymetry in the DTRM. Pumping has successfully been incorporated into the model; however, as expected it requires optimisation in order to be able to draw firm conclusions about its net economic benefit.

It is apparent that the Bristol Channel DTRM agrees well overall with tidal levels observed (and re-synthesised) at Hinkley Point and Avonmouth. In all cases, the N-RMSE is 3% or less, which is comparable with the results obtained with the CCSM and with the DCSM, and well below the 10% target set in this study. The tidal range is quite well predicted at Hinkley Point. A slight shift toward higher levels is noted at Avonmouth. This is reflected in the lesser MAE and N-RMSE values (compared to Hinkley), and could partly be attributedto the more detailed representation of the bathymetry up the estuary.

The 4 test simulations carried out have indicated that there is a good representation of the scenarios against the 0D modelling and against existing Severn models for the Cardiff-Weston.

Key findings regarding the simulations have developed; however, we would recommend that batch runs of the DTRM are completed in order to optimise each of the scenarios if the results are to be used as the basis for more detailed work

Publication Year:

2012

Publisher:

ETI

DOI:

https://doi.org/10.5286/UKERC.EDC.000831

Author(s):

HR Wallingford and Black & Veatch