To be honest, I made that name (and most others) up. There was a need to create a great number of original names. thus I used names that were drawn from a single "seed" of names that served as a basis.Finrod Felagund wrote: Rouavalda
I wondered a little about the name Rouavalda (and its fit with the name Dorwinion), but it can work I guess.
In OM15 you can find the second part of the rhovanic demographics, i.e the towns and settlements that were based on the overall numbers from OM14. In the primary TOR timeframe (TA 2946+) there are three principal towns in Rouavald that serve as the biggest centers. All of them are located along the lower Celduin, where the population density is supposed to be highest. You can find this on p. 104 of the revised Issue:Finrod Felagund wrote:[...] but how do the Rouavalda live? Do they have a central Town or Towns where the leader can control (tax) traders?
1. Leucir (Wen4) - ca. 3,100 inhabitants.
2. Hunthlaburg (Alm2) - ca. 3,100 inhabitants
3. Thausedir (Alm1) - ca. 4,400 inhabitants
Thausedir is supposed to be the realm's primary settlement, though especially on the lower Celduin there are other (see above) sizebale towns available for trade. There are even more upriver, but all of them are smaller. See the Issue for more details.
Concerning the Mardumhesta (Wainriders) and Bozorgana (Balchoth), Halbarad has already mentioned a lot. My general idea was that the Bozorgana did not give up on their expansionistic ambitions after Parth Celebrant, and Rohan (most likely with Gondor's help) had to fend off several more invasions (admittedly smaller ones). Eorl was slain in one of these. These continued attempts are reported by Tolkien and it is highly likely that the Balchoth were responsible.
After this they gave up trying to conquer the West and turned their attention northward (which was still not under their rule by now) and conquered Rhovanion up to the Celduin (at times even more, but generally the Celduin was the border). Soon after though, the central authority waned and the - quite large - Easterling empire fragmented into smaller successor princedoms that were often occupied fighting each other, making it so much easier for their neighbours to keep their independence. This disunity was probably the most important factor in the survival of independent Northmen realms (especially Dale) in these years.
This continued for about 450 years, when one realm began to re-unify the old empire step by step. Naturally, these Easterlings were heavily supported by and under the rule of Sauron. At the War of the Ring, official re-unification was not yet achieved (that was planned for the great victory celebration), but in fact they were again acting in unison. These Easterlings (Balchoth succcessors) were the main source of Easterling armies that threatened both Dale and were seen by Frodo & Sam (and fought at the Morannon).
So overall, I envisaged the Balchoth and their descendants as staying in Rhovanion from TA 2500 onwards, ruling it in various princedoms and being the single most dominant ethnicity here. But despite this, it is also true that the population density is quite low and the people are concentrated (relatively) in few areas wirh wide lands in between that are only very thinly settled.