No. You don't have to wade any stream above knee level. Levels may initially be low, but mountain streams tend to swell extremely fast especially during and after heavy downpour. Although we don't expect any issues, even in bad weather conditions, do not cross any stream if common sense tells you it might be dangerous to do so. In that case sms the Organisers Emergency Number (OEN) and ask for further instructions. In case a marshal is present, listen to his instructions.