[fishing4u2]

Greeting from a new poster and non-chemist.  I hope I'm on the right forum here for this question.  Please forgive the amount of background info preceeding the question.

I own and manage a small private pond which has multiple water sources with differing characteristics:

Source #1 are submerged, somewhat seasonal spring seeps over which I have no control.  Combined they are thought to be a minor contributor to total inflow.
Source #2 are spring seeps located upstream of the pond, visible at the surface, and over which I have some control (capture and diversion are possible).
Source #3 are two siphons which can divert water from an adjacent stream into a small, man-made spawning channel that leads to the pond, which permits the pond's wild trout to spawn naturally.  Each is controlled for discharge.  Combined or separately they can be the major contributor(s) to total pond inflow.

The spring water sources are typically about 50F, slightly acidic, and may not always have high levels of dissolved oxygen (D.O. can be enhanced by passive means, however).
The water siphoned from the stream varies from near freezing to a maximum of 65F, is slightly alkaline, and is very high in D.O.

The management goals for the pond include:
1) preservation/conservation of a wild strain of native brook trout formerly abundant in the stream.  The pond's population of brook trout (BKT) has successfully spawned for eight consecqutive years and appears to be stable. (its watershed has recently experienced some chronic as well as temporary perturbations associated with quarrying and ski-slope construction in the headwaters). 
2) preservation/conservation of a wild strain of rainbow trout (quite rare in this region).  Although rainbow trout make annual appearances in the spawning channel, and construct redds (nests), recruitment of developing embryos (in the gravel) to free-swimming RBT fry is much less successful (in only two of eight years have significant numbers of fry been produced).  Rainbow trout are known to require higher alkalinity than brook trout for reproduction.

Constraints

[fishing4u2]

Whoops, apparently hit the wrong button... thus the post above is/was incomplete!

(continued)

The pond is comparatively well shaded.  Nevertheless it's water will naturally stratify by day, especially with warm sunny weather.  At these times the warmer, less dense water near the surface (say, the top foot of six feet maximum depths) may slightly exceed the preferred thermal range of BKT.  Thus, discharge from the pond takes the form of multiple surface outlets which also serve to help skim detritus and algae that would otherwise use up D.O. during decomposition.  Underlying the warm surface water is thicker, colder layer of water which is generally close to the thermal optimum for trout.

In deeper bodies of water summer stratification can result in gradual depletion of D.O. the lower water column.  This is less likely to occur in this case, but is a consideration as the pond is protected from strong breezes that might otherwise keep the strata better mixed.  I am pondering whether or not I have a Catch-22: if I permit water sources #2 & #3 to mix prior to entering the pond, I temper the desirably cold spring water... but if I separate these two sources, introducing them into different parts of the pond (streamwater into the shallows; springwater into the basin) I might be making the deep, cold water refugia for the trout less productive for trout forage.   Various invertebrates which serve as food sources for the trout (especially crustaceans) prefer slightly alkaline water. 

My question...  If I capture the cooler, denser, lower pH, less well oxygenated spring sources and drop them (via an initial container for reaeration, and subsequently via a buried water line leading to the deeper, central basin of the pond,  will stratification prevent mixing of the higher and lower pH water, or will diffusion suffice to allow the siphoned stream water to 'sweeten' the spring water.  Again, the spring water runs about 50F, while the stream water could have a temperature of 65F. 

Any insights readers can supply are greatly appreciated.  I can be reached directly at fishing4u2@juno.com