The phrase "a small drainage" is correct and usable in written English.
It can be used when referring to a minor drainage system or feature, such as in landscaping or plumbing contexts.
Example: "The garden has a small drainage that helps prevent water accumulation during heavy rains."
Alternatives: "a minor drainage" or "a little drainage".
At the moment, Mr. Solomon said, the airport would like to build a small drainage channel to remove water seeping from a nearby lake; the water is encouraging plant growth that attracts birds, which in turn endanger landings and takeoffs.
Dendrogeomorphologic approaches were used to study hillslope erosion and valley floor dynamics in a small drainage basin in the Colorado Plateau of northeastern Arizona, U.S.A. Root exposure in pinyon pines indicated hillslope erosion averaged 1.9 mm/yr over the last 400 yr, but erosion has been highly episodic.
CONCLUSION: The use of a small drainage catheter after PCNL is associated with lower pain scores in the immediate postoperative period, yet no statistically significant benefit to the patient with regard to comfort is demonstrated beyond 6 hours.
Water continuously seeps from the base of the intact rip-rap dam that forms Lost Lake, forming a small drainage that continues for 75-100 m before joining with surface water flowing over the concrete spillway.
This includes redesigning the angles of some of the pathways so that the steps aren't too high or too steep, clearing out trash and digging a small drainage channel.
It has no influent streams: its source water is seepage from a small drainage area (42 ha) and wastewater.
In an agricultural catchment area in Germany we monitored an emergency overflow of a sewage sewer, an outlet of a rainwater sewer and two small drainage channels as input sources to a small stream.
This paired watershed study evaluated the impacts of SCM retrofits on hydrology for a small urban drainage area.
Late Quaternary landscape evolution was analysed with reference to a small (0.08 km2) drainage basin system in southeastern Gansu Province, southwestern Chinese Loess Plateau.
Another technique is to depressurize ahead by drain holes (or small drainage drifts on each side), an extreme example being the 1968 Japanese handling of extraordinarily difficult water and rock conditions on the Rokko Railroad Tunnel, using approximately three-quarters of a mile of drainage drifts and five miles of drain holes in a one-quarter-mile length of the main tunnel.
Japan's rivers are generally short and swift-running and are supplied by small drainage basins.
