Master Keyline Design: Water Retention on Contoured Land

This in-depth tutorial from the Australian Permaculture Research Institute details P.A. Yeomans' Keyline method for water retention on contoured landscapes, ideal for regenerative farming. Keyline design identifies the valley point where contours steepen, then plows parallel furrows on high points to spread water evenly. Planning uses CAD tools like Keyline Design software or Google Earth for ridge/valley analysis, marking primary Keyline (shoulder of valley) at 1-2% cross-slope. Chisel plow specs: 7-10 foot rigid shanks, 15-30cm spacing, ripping to 50-75cm depth in moist soil (post-rain), tractor at 5-8km/h. Earthworks sequencing: first rip along Keyline, then laser-level swales/dams on contours, followed by broadacre cultivation. Quantified results from 100+ acre farms show 30% soil moisture increase, 50% runoff reduction, and 2-3x pasture yield post-implementation. Video breakdowns cover dozer dam construction (1:3 batter slopes, clay core), subsoil ripping to fracture compaction, and seeding with legumes. Implementation steps: survey with theodolite for 0.5m contours, calculate dam volumes (e.g., 10ML/10ha via rainfall catchment), sequence ripping perpendicular to slope for even infiltration. Australian case studies (e.g., Yeomans' Nevertire farm) report aquifer recharge doubling within 3 years, with pasture carrying 2x livestock. Practical details include plow shank angles (50 degrees), fertilizer placement in furrows, and monitoring via neutron probes showing 20-40% water-holding capacity gain. This resource delivers precise tools, formulas (infiltration rate = slope x rainfall), and multi-year data for practitioners scaling water retention in dryland permaculture.