Rainwater Harvesting for Drylands and Beyond — Volume 2: Water-Harvesting Earthworks
About this book
Water is not merely a resource to be piped in, stored in tanks, and consumed — it is a dynamic force that shapes landscapes, sustains ecosystems, and, when thoughtfully managed, can transform arid and semi-arid environments from places of scarcity into places of abundance. This is the animating conviction of Brad Lancaster's Rainwater Harvesting for Drylands and Beyond, Volume 2: Water-Harvesting Earthworks, published by Rainsource Press in 2008. Where Volume 1 of the series established the guiding principles and observational strategies for understanding water in the landscape, Volume 2 moves squarely into implementation — providing detailed, illustrated guidance on the full range of passive earthwork strategies for capturing, slowing, and infiltrating rainfall before it can run off and be lost.
Lancaster writes from direct experience in Tucson, Arizona, where annual rainfall rarely exceeds 300 millimetres. On an urban plot of just over 500 square metres, he has demonstrated that passive rainwater harvesting — using no pumps, no electricity, and no complex engineering — can capture up to 380,000 litres of rainwater annually, supporting a productive landscape of food-bearing trees, native plants, and shaded outdoor spaces. This proof of concept is central to the book's argument: that passive water harvesting is not a marginal technique suitable only for experimental homesteaders, but a scalable and practical approach applicable from individual lots to entire neighbourhoods, farms, and watersheds.
The core principle underlying all the earthwork techniques presented in Volume 2 is deceptively simple: slow the water, spread the water, sink the water. Rainfall that falls on an unmodified slope tends to concentrate and accelerate, cutting channels, eroding soil, and departing the site as rapidly as it arrived. Earthworks intercept these flows, redirecting water horizontally across the landscape, spreading it broadly, and giving it time and space to infiltrate into the soil profile — where it becomes available to plant roots and recharges groundwater, rather than overwhelming stormwater infrastructure downstream.
Swales are among the most versatile and widely applicable earthworks described in the book. A swale is an on-contour trench — excavated precisely along the contour line of a slope — whose purpose is not to channel water but to arrest it. Water entering a swale spreads along its length rather than accelerating downhill, and the flat-bottomed trench provides an extended surface for infiltration.
The excavated soil is typically piled on the downhill side to form a berm, which serves both as a physical barrier retaining water within the swale and as a planting platform where moisture conditions are favourable for establishing trees and shrubs. Lancaster provides step-by-step guidance on reading topography, laying out contours, sizing swales to the catchment area they will serve, and sequencing multiple swales in series across larger slopes. Beyond swales, the book covers an extensive repertoire of earthwork forms suited to different site conditions, rainfall intensities, soil types, and intended uses.
Infiltration basins are broad, shallow depressions designed to receive concentrated flows from roads, paths, or rooftops, allowing large volumes of water to pond temporarily and percolate into the ground. Check dams are small, permeable barriers placed across channels or drainage ways to slow flow velocity, encourage sediment deposition, and promote infiltration along the channel bed. Berms in various configurations — level spreaders, diversion berms, brush weirs — direct sheet flows from impervious surfaces into vegetated areas.
French drains, gabions, and terraces address more specialised conditions involving steeper slopes, shallow soils, or specific crop-production contexts. A distinctive feature of Lancaster's approach is the integration of water harvesting with food production and ecological restoration. Earthworks are not conceived as isolated engineering interventions but as the foundation of a designed landscape.
Swale berms are planted with food trees whose roots stabilise the earthwork while drawing on the enhanced moisture regime. Native vegetation is prioritised where possible to reduce maintenance, increase ecological value, and ensure that the harvested water serves the broader ecosystem rather than simply individual plants. The book includes extensive guidance on selecting plant species appropriate to the local climate and soil conditions, sequencing establishment over time, and managing the transition from a newly shaped earthwork to a mature, functioning landscape.
Lancaster also addresses the important interface between buildings and water-harvesting earthworks. Roof catchment systems, gutter orientations, and the design of paved surfaces all affect where water concentrates and how effectively it can be directed into earthworks. He provides guidance on integrating passive earthwork systems with greywater recycling, discussing how household water can supplement harvested rainwater to support vegetation during dry periods while reducing the burden on sewage infrastructure.
The book is written in an unusually practical register for a technical subject, with numbered sequences of instructions, abundant photographs, and hand-drawn diagrams that illustrate each technique from multiple angles. Lancaster consistently emphasises starting with observation — reading the landscape to understand existing water patterns before reshaping them — and beginning with the smallest, highest earthworks in a sequence before working downhill, so that each new intervention benefits from the moisture conditions created by those above it. For green building practitioners, landscape architects, permaculture designers, and anyone working in water-stressed environments, Volume 2 of Lancaster's series offers an essential and highly practical handbook.
It makes the case not only technically but culturally: that regenerative water management is an act of ecological responsibility, community resilience, and quiet elegance — a way of working with natural processes rather than against them.