If the heat is rising and is below the meat it is direct as is your ECB. A UDS is a BBQ Pit not a smoker. Smokers are indirect heat ( the heat comes from out side the cooking area) BBQ Pits cook over live coal fire. All a waterpan does is act as a heat sink to maintain a Low temp. I don't use one and never have and if you know your equipment and how to manage a fire you don't need it to cook at lower temps.
I never met a Cow that I didn't like with a little Salt & Pepper! Certified PORK-A-HOLIC