If driving from Waimanalo heading north on Kalanianaole Highway, turn left onto Kumuhau Street. Follow Kumuhau and turn right on Waikaupanaha Street. Shortly after you pass Mahiku Place, on your right, there will be a fence and a gate, also on your right. Park along the street and proceed through the break in the fence. Proceed mauka along the dirt road. Maunawili Ditch Trail will be on your right. Note: If you continue up the dirt road, it will end at the Waimanalo side of the Maunawili Trail. This trail ends on Mahiku Place whereby you can walk the road back or the trail.
From the signed trailhead along Waikupanaha St., go around a yellow gate and proceed up dirt Maunawili Waimanalo Road. Reach a signed junction with another dirt road marked by two metal posts. Turn right and down on the side road, which is the Maunawili Ditch Trail. (Straight ahead the main road continues to the Maunawili Trail.) The wide trail initially swings right across a small gully. For a long stretch contour in and out of numerous gulches. Ignore mountain bike routes crisscrossing the main trail. At an umarked junction keep right and down. Decend gradually to reach the end of the ditch trail at another yellow gate. Go around the gate and turn right on paved Mahiku Pl. To return to your car, walk back along the road and turn right on Waikupanaha St.