The South African contingent had a successful day in general as Olympic gold medallists Cameron van der Burgh and Chad le Clos also finished atop the podium in their respective events.
Townsend won the gold medal in the men's 200m individual medley and the silver medal in the 200m freestyle.
He out-touched Hungary's Laszio Cseh in the 200m IM by 0.1 seconds in a time of 1:53.75 after a strong swim in the final freestyle leg of the race.
Cseh, an Olympic bronze medallist, finished second in a time of 1:53.85, while Japan's Daiya Seto touched third in 1:54.78.
Earlier, Townsend had to be content with second place in the 200m freestyle clocking a time of 1:43.95.
Australia's Tommaso D'Orsogna finished first with a time of 1:43.84 with his compatriot Robert Hurley clinching the bronze medal touching in a time of 1:44.05.
World record holder Van der Burgh once again burnt up the swimming pool in this event as he added another gold to the one he won in the 50m breaststroke the day before.
Van der Burgh led from start to finish as he blasted the rest of the field finishing first in a time of 57.22, with his closest rival Glenn Snyders of New Zealand taking second place with 58.13.
Japan's Daiya Seto claimed third place in a time of 58.60.
Fellow Olympic gold medallist Chad le Clos showed his class once again as he clinched gold in the 100m butterfly, bettering the African record he set in Dubai four days ago by 0.22 seconds in a time of 49.60 seconds.
He beat world record holder Evgeny Korotyshkin (50.22) of Russia to the wall with America's Thomas Shields taking bronze with 50.42.
The butterfly sensation won the bronze medal in the 50m butterfly and silver in the 200m butterfly on the first day of the meet on Saturday.
In the women's 400m individual medley South Africa's Katheryn Meaklim was off the pace in a sparse field consisting of only three swimmers as she finished third in a time of 4:46.05.
Meaklim lagged behind Hungary's Katinka Hosszu and Zsuzsanna Jakabos, who finished first and second in a time of 4:30.03 and 4:30.44 respectively.
Meanwhile, three-time Olympic medallist Roland Schoeman could not add anymore silverware to the gold and silver he won in the 50m butterfly and breaststroke the day before.
Schoeman just missed out on a podium finish in his specialist 50m freestyle event on Sunday as Australia's Kyle Richardson beat him to third place by 0.01 seconds.
The 32-year-old touched in a time of 21.54 with Richardson taking the bronze clocking 21.54. – Sapa