Refer to the diagram. A drainage system has a concrete inlet facility that incorporates a 10′ x 6′ x 6″ headwall. A 3′ inlet pipe and 2 identical 6′ x 6′ x 6″ wingwalls. How much concrete should be ordered? Do not include waste.

Refer to the diagram. A drainage system has a concrete inlet facility that incorporates a 10′ x 6′ x 6″ headwall. A 3′ inlet pipe and 2 identical 6′ x 6′ x 6″ wingwalls. How much concrete should be ordered? Do not include waste.