So I've been trying to find the article that referenced the effect that a decreased amount of water in your muscles would have on running. Unfortunately, I was unable to find it, but I did find a few other articles that helped shed more light and explain everything in such a way that it will be easy to implement.
The first article does a great job in explaining the effects of dehydration. It gives an example that mimics my previous question (which was what is the effect of drinking less fluids over time, which results in less water in your muscles) and shows a "3% decline in performance for each 1% decrease in body weight due to dehydration". The article can be found here.
The second article is a bit of a mish mash of virtually everything revolving around dehydration. Ultimately what I got out of it for myself was that the serious cramping from the marathon and the soreness at the end of the recent half marathon is a combination of factors. Numero uno is, of course, dehydration. Granted, I drank a decent amount of water during the half marathon, but I wasn't well hydrated before the race. I hadn't had much water the day before and only had a little bit of water just before the race. So with decreased water comes decreased oxygen flow to the muscle. Add to both of these the drop in potassium and you have cramps. So what I needed was to drink more water and to also control the potassium level in my blood in order to prevent cramping in the calves. The article can be found here.
Finally, the third article is a pretty good article because it does a very good dissection of marathon running and its effect on your body, including dehydration. It is short and succinct, giving a clear picture of what our bodies go through when running such long distances. The article can be found here.
What it all boils down to is drink more fluids, both before, during and after a race. Doing as I have recently, that is drinking more soda than water, certainly decreases the amount of water in my muscles which will automatically handicap myself. So hydration is an ongoing matter (duh! I am still learning the basic tenements of running I guess, and I will probably still be learning them years down the road), one that should not be a "I know I've been eating and hydrating bad these last few weeks/months, but I will make up for it by eating and drinking better the week before the race". Not only does this make you under perform during your training but it will also make you unprepared for race day.
Lesson learned (again!).