The Sandy Springs City Council has increased by $19,014 the design budget for the proposed makeover of the Northside Drive-Riverview Drive-Old Powers Ferry Road crossroads to account for a retaining wall northwest of the intersection.

The council approved a supplemental agreement with HNTB Inc. increasing the design contract’s value to $265,968. The consultant began work last October, and public comment was gathered at a February open house and subsequent 30-day comment period.

“Before recommending additional concepts, the city needs to determine the type and approximate size of the retaining wall needed in the northwest quadrant of the intersection,” Interim Public Works Director William H. Martin said in memo on the effort, designated a TSPLOST (Transportation Special Purpose Local Option Sales Tax) Traffic Efficiency Project.