Water Management in Gerasa and its Hinterland

The Decapolis city of Gerasa has seen occupation since the Bronze Age but reached its zenith in the Roman to early Islamic period as a population centre and trading hub. Located in a fertile valley in the limestone foothills of the Ajlun mountains, the city benefitted from a benign climate and an excellent local water supply from karstic springs and perennial streams. By the Roman–Early Byzantine period, these water sources were harnessed and managed by extensive aqueduct and distribution networks that satisfied the broad range of water needs of both urban and rural dwellers.
   This volume offers an up-to-date, comprehensive, and multidisciplinary analysis of the water management system employed in both Gerasa and its hinterland from the time of Roman occupation to the devastating earthquakes that struck the city at the end of the Umayyad period. Drawing on archaeological evidence from the author’s field research, together with a critical and detailed analysis of the evidence of water installations and the results of a radiocarbon dating study, this insightful book offers the first diachronic interpretation of Gerasa’s water distribution, setting the city in its geoarchaeological, historical, and landscape contexts, and contributing to the broader understanding of its archaeological history.

List of Illustrations

Author’s Preface

Acknowledgements

Abbreviations Used in the Text

Glossary

Chapter 1. Introduction

Volume Content

Part 1. Study Approach and Contextual Background

Chapter 2. Information Sources and Methodology

Introduction

The Study Area

Chronology and Naming Conventions

Previous Studies Related to Water Management

Water Management Studies in the Study Area

Water Management Studies in the Southern Levant

Past Field Surveys

Primary Literary and Non-Literary Sources

Secondary Literary Sources

Nineteenth-Century Sources

Post-Nineteenth-Century Sources

Visual Sources

Ground Photography

Aerial Photography

Satellite Imagery

New Field Surveys

Terrestrial Carbonate Studies

Background

Materials and Methods

Archaeometry

Overview

Radiocarbon

Dating

Chapter 3. Natural Environmental Contexts

Physiography and Geomorphology

Topography and Relief

Palaeolandscape History

Climate

Modern Climate

Palaeoclimate

Geology

Pre-Quaternary Geology

Quaternary Geology

Regolith

Soils

Colluvium

Vegetation

Hydrological Setting

Surface Hydrology

Subsurface Hydrogeology

Springs

Seismic History

Seismological Setting

Earthquake Record in Gerasa

Discussion

Chapter 4. Historical Contexts

Introduction

Surface Surveys

Settlement History

Pre-Bronze Age

Bronze Age

Iron Age

Hellenistic Period (332 bc to 64 bc)

Nabataean Period (300 bc to ad 106)

Roman Period (64 bc to ad 324)

Byzantine Period (ad 324 to 640)

Umayyad Period (ad 640 to 750)

Discussion

Part 2. The Hydraulic System

Chapter 5. Water Sources

Introduction

Surface Runoff

Impermeable Surface Runoff

Permeable Surface Runoff (Overland Flow)

Groundwater Sources

Wells

Springs

The Relationship between Water Availability and Settlement Location

Discussion

Chapter 6. Water Transport

Transportation by Natural Surface Flow

Artificial Structures Employed to Control and Harness Hillslope Runoff

Channel Flow Structures

Transportation by Spring-Fed Aqueducts

Rock-Cut Aqueducts

Aqueducts Constructed of Masonry or Field Stones

Pipelines

Aqueduct Bridges

Conduit Hydraulics

Methods Adopted to Overcome Issues Affecting Aqueduct System Design and Operation

Aqueduct Networks

Aqueduct Statistics

Upper Jarash Valley (Upper Wadi Suf ) Sector

Central Jarash Valley Sector

City Area–East Bank Sector

City Area — West Bank and Bab Amman

Southern Jarash Valley Sector

Jarash–Zarqa River Junction Sector

Majarr–Tannur Valley Sector

Control and Management of the Aqueduct Networks

General Comment on Water Rights

Control of Water Resources in the Study Area

Carbonate Sediment Lining Aqueducts

Dating of Aqueducts

Radiocarbon

Dating

Evidence for Pre-Roman Aqueduct Networks

Discussion and Conclusions

Chapter 7. Water Storage

Introduction

Reservoirs

Intramural Reservoirs

Possible Reservoir Installations

Extramural Reservoirs

Reservoirs South of the City

Storage Basins

Intramural Storage Basins

Extramural Storage Basins

Cisterns

Intramural Cisterns

Extramural Cisterns

Discussion

Chapter 8. Water Use

Private Use

Public Use

Bathhouses

Fountains

Ornamental Basins

Latrines

Ecclesiastical Use

Cultic Use

Primary Industry Water Use

Agriculture

Extraction Industries

Secondary Industry Water Use

Textiles and Leather

Watermilling

Olive Oil

Potteries

Wine Production

Metal and Glass-Working

Discussion

Part 3. The Urban Network

Chapter 9. Urban Water Infrastructure

Water Transport Installations

Extramural Aqueduct Networks Supplying the City

Aqueducts within the Western Side of the City

Aqueducts within the Eastern Side of the City

Pipelines

Water Storage, Flow Regulation, and Distribution Installations

Reservoirs and Storage Basins

Piscinae and Flow Regulation Basins

Water Distribution Installations (castella divisoria)

Drainage and Sewage Disposal Installations

First-, Second-, and Third-Order Drains

Fourth-Order Collector Drains

Sewage Disposal

Discussion

Chapter 10. The Combined Intramural Water Transport, Storage, and Distribution Network

Areas Serviced by the Main Supply Aqueducts

Methodology

Interpretation

Distribution to castella divisoria

Evolution of the Urban Water Distribution and Storage System

First Century bc/ad to ad 106

ad 106 to ad 150

Second Half of the Second Century

Third and Fourth Centuries

Fifth to the Mid-Seventh Centuries

Mid-Seventh Century to ad 750

Discussion

Changes in Urban Water Management in the Byzantine Period

Changes in the Physical Environment

Societal Changes

Changes to the Water Distribution System

Discussion

The Gerasene Water Management System in the Context of the Decapolis

Sources

Aqueducts

Storage

Hydraulics

Urban Distribution Network

Irrigation

Discussion

Chapter 11. Conclusions

Water Sources

Water Distribution and Storage

Aqueducts

Storage

Urban Water Supply and Distribution

Water Use

The Effects of Climate Change and Natural Disasters

System Management

The Impact of the Hydraulic System on Development

Concluding Remarks

Part 4. Appendices

Appendix A. Early European Visitors to Jarash

Who Recorded Water Features: 1812–1875

Appendix B. Early Aerial Photographic

Coverage of the Study Area

Appendix C. Jarash Water Project Site Database

Appendix D. Radiocarbon AMS dates

Appendix E. List of Seismic Events in Gerasa

Appendix F. Catalogue of Important Springs

Appendix G. Catalogue of Recorded Aqueducts

Appendix H. Bathhouses

Appendix I. Fountain Catalogue

Appendix J. Castellum Catalogue

Appendix K. Flow Rate Formulae

Bibliography

Index of Localities