Yes, but you usually need to do a site visit too. It's good to think of this from a risk perspective, both in terms of ecological values from low to high value, and the likely impacts of your development from a low potential impact to a high impact. If you're dealing with a simple system, say a “Los Angeles-style” concrete drain and you simply want to install a culvert, it's likely that you will only need to do a desktop assessment. However, if you're looking at a more complex environment, such as a stream or wetland, where there's a range of habitats and it's clearly more natural, you're much more likely to need some field work and some sort of ecological sampling. We generally do a site visit unless we have personally done some sampling in that area within the last couple of years. In such a situation, we’d be confident we've got enough information to understand the ecological values at that site, so we can advise how to protect them.