1 Introduction

Peat is the living and dead, partially decomposed organic matter (mostly plants), that forms the soil matrix of peatlands. Peatlands are wetlands that contain peat; the peat deposit can be considered a shallow unconfined aquifer. This book focuses on the nature of soil water and groundwater exchanges to, from, and within peatlands and the adjacent ecosystems or underlying sediment. It considers the ecohydrological feedback between the landscape that controls the form and function of the peatland and the peat matrix itself that modulates groundwater flows.

The morphology of peatlands is controlled by the interaction of groundwater flow with the ecological processes that create and destroy peat. Where the water table is high, peat can form; where the water table is low, peat decomposes. The shape of the peat surface, in turn, controls the position of the water table and the associated surface water and groundwater flows. In peatlands, groundwater flow and the shape of the ground surface are tightly coupled.

Peatlands can occur as peatland complexes or isolated peatlands based on their connection to other peatlands. Peatland complexes exchange groundwater with the regional aquifer as well as with other types of peatlands. In contrast, isolated peatlands are linked only to the local groundwater system. Peat is the matrix of which all peatlands are built, and its character both reflects and modulates local and regional groundwater systems. Given the distinct nature, character, methods, and applications of groundwater hydrology in peat and peatlands, this book provides a resource for students, researchers, and practitioners pursuing groundwater studies in this type of land cover.

This book begins with definitions of peat and peatlands and how their interaction with the landscape controls their form and function. Then it focuses on the specific properties of peat that control groundwater flow and solute transport and examines the nature and outcome of disturbances to peatlands. The book closes with a discussion of appropriate methods for assessing the hydrology and hydraulic characteristics of peat.

This book is not intended to be a literature review; rather, it is a compendium and synthesis of groundwater and soil-water processes in peat and peatlands and methods for assessing them based strongly on our own collective knowledge and experience. We provide citations to encourage and support further exploration of the processes and issues.