The utility model discloses a regulating reservoir using a construction
adit as an underground
cave depot capacity expansion. The regulating reservoir comprises a regulating reservoir body, the construction
adit, a
water delivery tunnel, a surge shaft, a flow control facility and a plugging body. The regulating reservoir is positioned at the downstream of the flow control facility and plays a role in regulating a downstream
water delivery pipeline communicated to a water
plant; one end of the construction
adit is connected with the regulating reservoir, and the other end of the construction adit is connected with a tunnel section of the
water delivery tunnel at the upstream of the surge shaft; the water conveying tunnel is a main flow passing channel, and the surge shaft is located on the upstream of the
tail end of the water conveying tunnel and arranged close to a flow control facility as much as possible. The flow control facility is located at an outlet of the water delivery tunnel, the upstream is connected with the water delivery tunnel through a
branch pipe, the downstream is connected with the regulating reservoir, the flow control facility comprises a flow regulating valve and a
power station, and the flow regulating valve and the
power station are arranged in parallel; the plugging body is arranged at the intersection of the construction adit and the water delivery tunnel and used for sealing the inner end of the construction adit. The utility model has the advantages that the construction land is saved, and the building materials are saved.