Fatigue and frustration are growing among rescue workers who are ending another long day of searching for those who perished in last week's Hill Country flood disaster. 

Some volunteers involved in the search are even resorting to on-site IV injections to get through the hottest day yet in the Guadalupe River basin, where there could be remains of more than 100 people. 

While there is not much that can be done at night because it's so dark, there are some people who are continuing the very slow, methodical process of untangling huge debris, where most of the remaining missing victims are believed to be. 

Josh Kothman holds Alex Long by the ankles over a still swift-moving section of the Guadalupe River. They are using tools including chainsaws to remove branches, trash and other debris that becomes lodged along bridges and banks, and where often search crews are finding the victims of last week's flood disaster. 

There's no telling what the debris balls contain, but they can take hours to untangle, and the strong current from the river only makes the work more difficult. 

"It's definitely dangerous," said Kothman.

Kothman is working with Texas Team 136 Search and Rescue. 

"I'm out of College Station," said Kothman. "I essentially just got a phone call to come help, and I came running. All my family's from Fredericksburg and Kerrville, so it's personal for us."

It's the hottest and most humid day yet on the river basin since this process began five days ago with searches by air and ground continuing even in areas where the water receded days ago. 

"Long, hot nasty days," said Capt. Eric Cracraft with the Comfort Fire Department. "It's just getting to these brush piles. I've been in piles that were the size of school buses. They're big, they're massive, and they are everywhere."

Some volunteers are receiving IV injections during breaks. 

Many volunteers said there is a lack of coordination or instructions from anyone who may be in charge. 

"I think it needs to be delegated and spread out. There needs to be a little bit more communication. And it's hard."

It's also hard recovering personal items from the young girls swept away from Camp Mystic, including a Bible. 

J.C. Wheatcraft, who is using pumps to drain a quarry filled with flood water right next to the Guadalupe, says he was at his sand and gravel mine early Friday morning and heard screams for help coming from the raging river.

"It's hard to put all of this out of your mind, to go to bed at night, you know, and to think, if I'm not out there right now, what if somebody is right there that is still waiting?"

That's why these rescue and search volunteers remain motivated in the face of so much adversity. 

They feel they owe it to these still missing men, women and children. 

• Rescue
• Texas
• Flooding