Pond systems for the production of microalgae biomass have evolved over the past 30 years from the early meandering (folded) channel designs with propeller pump mixing introduced by Oswald. 1 Ponds now in use incorporate a wide range of configurations employing various methods for mixing, feeding, control of algae populations and contaminants, enhancement of productivity, etc. Rather than try to cover all of the various options in a general way, much of which is discussed elsewhere, this chapter will concentrate on the single loop paddlewheel mixed design which has proven successful for a number of applications at relatively large scale. Elements of planning and design will be discussed beginning with considerations of site selection and layout of facilities, pond configuration, hydraulics, and size, followed by details of paddlewheel design, settleable solids control, pond bottom lining and wall construction, and utility services. Construction factors and their influence on design will also be discussed.