According to "Indivisible Richardson", there was a "223% Increase in Democratic turnout in May 6 election." I think that refers to Collin County races, not the City of Richardson, but if true and if it carried over to Richardson, that might explain Cory Montfort's surprisingly (to me) good showing in her city council race, losing by only 284 votes out of 5,488 total. She didn't explicitly run as a Democrat in this non-partisan race, but if asked she didn't try to hide her party leanings either.
In my pre-election analysis, I didn't even try to factor in a surge of Democratic votes because it was a non-partisan race and, besides, I didn't remember any surges of Democratic votes around here before. Even though there had been some. In 2008, the Obama wave helped Democrat Carol Kent upset 20-year incumbent Republican Tony Goolsby in Texas House District 102. And just last November, Hillary Clinton out-polled Donald Trump in House District 32, considered a safe district for Republican Pete Sessions. But I still didn't factor a Democratic surge into my pre-election analysis this year. My bad.
Maybe. Before one puts too much stock in this claim, note that Kashif Riaz explicitly highlighted his support from Democrats but he garnered only 24% of the votes in his Place 5 race. So if there was a Democratic surge, it was highly selective. Also, note the source of the claim: a Democratic activist speaking to an audience of Democratic activists in Collin County.
So, was there a surge? We can see a surge in total voting in Richardson city council races in 2017 compared to 2015. Those 5,488 votes in Place 4 in 2017 doubled the number of votes in the most popular race two years ago, Place 1 with 2,708 votes in 2015. But determining how many of those additional voters were Democratic voters as opposed to Republican voters or independents is more speculative. Still, a Democratic surge is an interesting claim. Someone needs to do a systematic study of turnout in CoR and RISD races.