I have a storm drainage system that has a flow splitter to some treatment devices.  Gate valves are shown on each side of the flow splitter for either spill control or maintenance purposes, i.e. flow to treatment devices can be shut off while performing maintenance.  I normally show gate valves for this purpose.  I had a peer tell me to use a plug valve instead, as it is better at creating a good seal when flow streams in drainage systems have some grit and such.  However, I am concerned about the reduced port area that would restrict gravity flow, and I have heard plug valves are very hard to operate and if they are not maintained can be impossible to budge later on.

Probably best choice for storm or waste water, is "None".
Gate valves are NOT designed to be used as throttling or flow control vales . They are intended to be shutoff valves to remain fully open or fully closed.

Other types to consider are :

Plug Valve
Slide Gates
Swing Gates
"Duck bill: Tide or backwater valves
Tainter Gates

Several valve makers offer Free Advice including
Globe
Golden
Crane
Many, many others

Several standards and professional groups such as AWWA, WPCF,
ASCE
The Ten State Standards
and your local agencies having jurisdiction will also offer advice, even if not asked.

Double disk gate valves will not go drip tight because the sediment in the groove will prevent the valve from fully closing.  Proper operation in a pressurized system with flow can clear the debris.  (close, open 5 turns, close, open 3 turns... until the valve will not close any tighter)

Resilient seat gate also know as wedge valves will have less of a problem since there is no groove but if there is debris in the gate area that cannot be crushed or flowed out, the valve will still leak.

Plug valves are better at sealing against this problem because they slide the debris away (or attempt to) but if the debris is tightly adhering to the sealing surface it make the valve very hard to operate.

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