I'll wait for a qualified person to answer your question, but here's /u/MI13's relevant answer to a similar question, /r/AskHistorians: "Last night's GOT had me thinking about a question I've had before: Who pulls out the dead and wounded during a melee battle?"

There's an example I'm aware of that's not medieval or European but was fought with hand-to-hand combat weapons and involved bodies stacking up. It's a fairly famous battle in Hawaiian history called the Battle of Kepaniwai ("damming of the waters") and took place in the Iao Valley on Maui in 1790. The battle lasted several days and accounts have the bodies piling so high that they dammed the river that flows through the valley. Accounts also have the river's water turning red from all the blood.

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The battle was between the forces of Kamehameha (ruler of the big island at the time) and the forces of Kahekili and his son Kalanikūpule, who controlled Maui, Oahu and several other islands. There were somewhere in the neighborhood of 1,000 men on each side. They fought with clubs, spears, and paddle like weapons edged in shark teeth called leiomano. There were 2 cannon and some firearms involved in the battle on Kamehameha's side but according to accounts, those were mostly only effective for shock and awe and had limited effectiveness in creating casualties. The cannon were also exceeding difficult to move over the terrain (mostly narrow footpaths). Canon and firearms were new to Hawaiian warfare at the time and this was one of the first battles in which they were employed.

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The narrow sides to the valley and the flow of the water undoubtedly contributed to the stacking up of the bodies but the death toll still had to be pretty substantial to create a dam. There is no actual body count from the battle of which I'm aware. Most of the major players escaped to fight another day.

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If you're ever on Maui you can hike the trail back up into the valley. It's part of a state park and stunningly beautiful.

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Although it does come with some of the stereotypical baggage of the era, Abraham Fornander's book on the history of the Hawaiian people written about 100 years later is a good resource if you want to know more.