Hydrodynamic Cross-Scale Archaeology at a Roman River Harbour

León-Carlos Dempwolff,Renate Gerlach,Oliver Lojek,Nils Goseberg,Valeria Selke

doi:10.3390/w12123365

Abstract

Trans-disciplinary research methods and data from archaeology, geology, hydrology, and hydraulic engineering are successfully merged to reevaluate hydrodynamic effects of Roman hydraulic structures at a Rhine river harbour. The archaeological site Colonia Ulpia Traiana, is characterized by its exceptional preservation, providing ample research data on its river harbour. Constructed by the Romans, the berthing area is lined by a wooden quay-wall. Setting this harbour apart is its up-stream tip, which is fitted with a unique hydraulic structure with unknown purpose. Structure related hydrodynamic impacts on the historic Rhine regime are examined by introducing a novel cross-scale multi model approach, consisting of three steps: (i) Scaled physical experiments are performed to investigate the roughness influence of the wooden quay on a local scale. (ii) A numerical representation of the physical experiments is done in Delft3D, validating a linear loss term to accurately capture the roughness influence on the velocity distribution. (iii) A mid-scale Rhine river model of the area is generated that approximates the historic river bathymetry through morphological evolution. The quay-wall is implemented in parametric form and induces a substantial velocity reduction throughout the harbour. The unique structure exhibits hydromechanic properties mimicking present day current-deflection walls, potentially rendering it their primal prototype.

Highlights

Hydraulic engineering of harbours can be traced back to ancient civilisation such as the Greeks constructing the ports of Pylos (Lat: 36.935 793; Long: 21.687 064) and Methone (Lat: 40.467 450; Long: 22.583 650) as early as 600 BC or the Romans constructing a port at the Tiber estuary near
From the initial usage of natural bays as berthing areas and the reinforcement of riverbanks and beaches using kid bindings to wooden jetties, the Romans progressed to the accomplished construction of seaports inventing the opus caementicium for underwater usage and sinking stone filled barges in place as foundations [3,4]
The black-yellow line represents the depth-averaged velocity resulting from the numerical flume model (NFM)

Summary

Introduction

Hydraulic engineering of harbours can be traced back to ancient civilisation such as the Greeks constructing the ports of Pylos (Lat: 36.935 793; Long: 21.687 064) and Methone (Lat: 40.467 450; Long: 22.583 650) as early as 600 BC or the Romans constructing a port at the Tiber estuary nearCentumcellae (Lat: 41.780 032; Long: 12.262 886) 700 years later [1,2]. Water 2020, 12, 3365 one of the only two coloniae in the province of Germania Inferior and the second largest city after. Between 98 to 106 AD [8] the settlement was elevated to the status of a Colonia by the Roman Emperor Trajan and called CUT. It became a city after the Mediterranean model with a chess board street system, city walls and large public buildings such as the forum, capitolium, temples and baths [9,10,11,12,13,14,15,16,17,18]

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