Geography. A subject about rocks, water, and the shape of land that we all learned back in elementary school. Why were we taught this? Beats me, but in some strange way, it relates to this fun game of ours called fantasy football.

In a basic sense, a “stream” is a small body of water without much of a purpose in an ecosystem. Similarly to the geographical definition of the word, in fantasy, the position we “stream” usually doesn’t have much of an impact on our team.

But sometimes, that tiny stream turns into a river (there is a point to this, I promise). Many resourceful owners took a gamble on guys like Nick Foles and Josh McCown to be their “stream” at quarterback while the rest of their team brought home the bacon.

In the cases of those two streams, they've turned into rivers - a large body of water with a current that supports life and transportation, among other things. When an owner stumbles into one of these “fantasy rivers", they don’t need to rely on streams anymore, as those “fantasy rivers” like Foles and McCown take you to the ocean. AKA, your league championship.

The moral of this story and geography lesson is that I hope you've found a river, as the streams are few and far between this week. This far into the fantasy season, we usually know who the usable fantasy quarterbacks are, which makes it increasingly hard to find non highly-owned stream options. But if you're still swimming in streams trying to find that elusive ocean, here are Week 15’s top waiver wire quarterbacks.

Top Plays

Ryan Tannehill, Miami Dolphins (Owned in 14.1% of ESPN.com Leagues)

With the Dolphins running game still in shambles, the Dolphins have turned to their quarterback, letting him throw until he can’t no mo’. The Dolphins are third in the NFL with a 1.83 pass/run ratio, and it’s having a great impact on Tannehill’s fantasy numbers.

With at least 18 points in his last three contests and double-digit fantasy points every single week this year, the second-year quarterback has become quite the safe streaming option despite his low ownership. Expect the success to continue this week against New England.

After a great start to the season where they spent a lot of time in the top three, the Pats have slipped down to ninth on the year in Defensive Passing Net Expected Points per Pass when adjusting for schedule. They simply haven’t been able to overcome all the injuries in their secondary, and Tannehill should take advantage.

Joe Flacco, Baltimore Ravens (Owned in 53.7%)

I suggested Flacco as a solid option last week, and despite the snowy conditions, he came through with 20 standard fantasy points. And if it weren’t for three interceptions, he would have had a top-five day at the position.

Flacco has a chance for repeat success this week against Detroit, a team coming off a loss to the Eagles in which they surrendered almost 20 fantasy points to Nick Foles in horrible throwing conditions. The Lions rank 22nd on the year in pass defense according to our metrics, and don’t seem to be improving this time of year. Flacco has had a bad year on the field, sitting outside the top 25 in Pass NEP, but he showed last week that a soft matchup can be all he needs to be successful in fantasy.

Jason Campbell, Cleveland Browns (2.3%)

With a 2.10 pass-to-run ratio, it doesn’t really matter who starts at quarterback in the Factory of Sadness, as the fantasy points follow. Jason Campbell will start again this week for Cleveland, and will look to add on top of his 30.3-point performance last week. The perennially underrated veteran has scored at least 21 points in three out of four of his starts this year, some of which can be credited to the emergence of stud receiver Josh Gordon.

Campbell’s three games above 21 points have come against three top-18 pass defenses in Kansas City, Baltimore, and New England. If Tannehill and Flacco are owned, don’t hesitate to plug-in and play Campbell.

Quick Hits with a Dose of Risk

Matt Flynn, Green Bay Packers (1.4%)

Flynn showed some degree of competence last week against Atlanta after his abysmal effort on Thanksgiving. The league leader in Net Expected Dollars Made per Game Played has had mild success (14.1 points per game) against two bottom-six pass defenses in Minnesota and Atlanta this year. While Dallas isn't as bad, they've allowed the most fantasy points in the NFL to opposing quarterbacks.

Matt Cassel, Minnesota Vikings (0.9%)

Cassel has thrown for at least 240 yards in each of his four starts, and is coming off of a 19.2 point game against Baltimore. The advanced metrics give Cassel a pat on the back as well, as he is remarkably tied for tenth on the year in Pass NEP per Pass at .11, albeit on 165 attempts.

The Vikings take on the Eagles, a below average pass defense, and will likely be without Adrian Peterson this week. Recent success + no run game + solid matchup=“meh”?

Honorable Mention: If Kirk Cousins does indeed start, he should be a top streaming option against the worst secondary in the NFL in Atlanta.