To enable plants to grow in a waterway formed of concrete blocks by forming a cut part from a top on a side wall, with the side wall being formed in U shape in section perpendicular or inclining to the outer side, and installing a lateral fence member in the cut part.

In a side wall part of almost perpendicular concrete block having a U shape in section, a cut part 2 is formed from its top to the side wall part. A cut part 3 is formed from the top to the bottom surface part, and if necessary the cut parts 2, 3 are formed on both side malls in a face-to- face relation. Anyway, the formation is made by performing cutting from the top of the side all to the downward, then a cut stepped part is arranged at an end of lateral fence board member or lateral rod member to perform the engagement with the cut parts 2, 3. For example, the block 1 having the cut parts 2, 3 in the part of its concrete block for general waterway is used, wherein water passing quantity is stabilized even at the time of water increase. Accordingly, the strength or durability as a block waterway is ensured, leading to improvement in the water side atmosphere therearound.