The somewhat unsatisfactory answer is "it depends". Scale and location matter significantly with NbS solutions. Grey infrastructure, such as seawalls or dams, can have much higher capital costs at the front end for permitting and construction, relative to NbS. NbS can require larger land footprints than grey infrastructure to achieve desired benefits, so costs could be significant where land value is high. It is important to understand the opportunity costs of implementing NbS when other land uses are in consideration (e.g., agricultural or urban development). Planning for NbS should also take into consideration ongoing maintenance costs (e.g., irrigation or fertilizer to establish plantings, ongoing mowing or weeding to maintain desired vegetation assemblages).