An apparatus for forming a water storage material from a biomass input material using supercritical or subcritical fluid processing, the water storage material capable of absorbing a liquid and releasing the liquid. The apparatus utilizes supercritical fluid processing, subcritical fluid processing, charring, or a combination thereof. The apparatus includes a controller configured to control the apparatus. The apparatus further including a processing station configured to hold the biomass input material, and to use the biomass input material for processing into the water storage material.