I'm a firefighter in Garland and that area is in my district. After heavy rains, Rowlett creek turns in to a raging river. We've had to rescue several kayakers before. During normal flow, parts of the creek are only a few inches deep. In the right conditions you can go all the way to the lake, but i'd go with spazm09 and paddle up from the lake. Fishing is best on the creek during the spring anyways. Just be safe.