Hi SCUBA-licia,
From what you are saying I assume that you are looking at a model for deciding on what equipment and techniques to adopt regarding dive location, conditions and activity. You may also want to predict and resolve significant problems that may emerge during the dive. May I suggest the risk management model. There are two books recently published which explain the risk management model and its implementation.
"Risk Management for Diving Operations" and "SCUBA Diving Operational Risk Management".
Standards, policies, procedures, rules and legislation are fine as a starting point, and they will facilitate rapid deployment into a dive activity. However, they are based on a known and defined situation. If you venture outside the known and defined situation, you need a model that enables you to adapt human and physical resources to the unknown and the uncertain. Risk management facilitates this process.