July 9, 2026
Safety Focus
Part 4 of 4: Acclimatization and the Danger of the First Few Days
If you remember one statistic from this week, make it this one. According to OSHA, almost half of heat-related workplace deaths occur on a worker's first day on the job or first day back after an extended absence, and over 70 percent occur during a worker's first week. That finding, drawn from an analysis of OSHA heat fatality investigations (Tustin, 2018), is the single most actionable fact in heat safety. The victims are overwhelmingly people whose bodies had not yet adapted to the heat.
Acclimatization is a real physiological process, not a toughness contest. Over one to two weeks of gradually increasing heat exposure, the body learns to sweat earlier and more efficiently, retain salt better, and run a lower heart rate under the same load. A new hire has none of those adaptations on day one, no matter how fit or experienced they are. Neither does your best hand coming back from two weeks off.
OSHA and NIOSH both endorse the Rule of 20 Percent for new workers: no more than 20 percent of a normal shift's duration and intensity in the heat on day one, then 40, 60, and 80 percent on the days that follow, reaching a full schedule on day five. For experienced workers returning after an absence, NIOSH gives a faster ramp: 50 percent exposure on day one, 60 percent on day two, 80 percent on day three, and 100 percent on day four.
On a drill site, that means the new guy spends his first days on lighter tasks, in shade where possible, with more frequent breaks, while a supervisor or buddy actively watches him. It is not coddling. It is running the schedule the fatality data demands. Summer help hired this month is exactly the population the 70 percent statistic describes.
Key Takeaways
• Almost half of heat deaths happen on a worker's first day or first day back. Over 70 percent happen in the first week.
• New workers: 20, 40, 60, 80, then 100 percent heat exposure over the first five days.
• Returning workers: 50, 60, 80, then 100 percent over four days. Assign a buddy to watch anyone on a ramp-up schedule.
Sources:
• OSHA: Heat: Protecting New Workers
• CDC/NIOSH: Heat Stress Acclimatization
Industry Update
The Colorado River’s Rulebook Expires This Year: Here’s Where Things Stand
The agreements that have governed the Colorado River for nearly two decades all run out at the end of 2026: the 2007 Interim Guidelines for Lake Powell and Lake Mead, the 2019 Drought Contingency Plans, and related arrangements under the 1944 treaty with Mexico. What replaces them will shape water supply decisions for 40 million people across seven states, and the deadline is firm. The Bureau of Reclamation has stated that a decision on post-2026 operations will be made before October 1, 2026, the start of the 2027 water year.
Here is where the process stands. Reclamation released its draft Environmental Impact Statement on January 9, evaluating five operational alternatives without naming a preferred one, deliberately leaving room for the seven basin states to reach their own agreement. The comment period closed March 2 after drawing more than 18,000 submissions. The states, despite negotiations running since 2022, have not yet produced a consensus plan, which leaves the Department of the Interior positioned to set the rules through the federal process if they cannot.
For the groundwater industry, the direction is clear regardless of which alternative wins: every acre-foot cut from surface deliveries pushes cities, districts, and farms across the Southwest toward wells, recharge, reuse, and brackish supplies. If your work touches Arizona, Nevada, California, or the Upper Basin states, the next 90 days of this process are worth following. We will cover the decision when it lands.
Sources:
• Bureau of Reclamation: Colorado River Post-2026 Operations
• Bureau of Reclamation: News Release: Draft EIS for Post-2026 Operations (January 9, 2026)
Knowledge Share
Part 4 of 4: Filter Pack Material, Ratio, Thickness, and Placement
The pack itself gets specified on four counts: what it is made of, how it is sized against the formation, how thick it is, and where it goes. Material first: Specify clean, washed, well-rounded siliceous material with a specific gravity of at least 2.5 and acid soluble content of no more than 5 percent. Crushed, angular, or limey material packs poorly, dissolves in acid treatments, and is not worth whatever potential savings may be realized.
Sizing is all about ratios. The pack grain size should usually range from 4 to 6 times the formation grain size, the familiar 4:1 to 6:1 pack to formation ratio, with a multiplier of 4 for fine, uniform sand and up to 6 for coarse, well graded material. Generally 6:1 is the top end, but some successful well designs have gone as high as a 9:1 ratio. Here is the point that separates good designs from folklore: it is the ratio, not the thickness, that controls sand. A pack sized right at 3 inches thick stops sand; a pack sized wrong at 12 inches does not.
Which brings us to thickness. A100-20 sets a ceiling of usually no more than 12 inches, but read that as a limit, not a target. The practical guidance from Groundwater and Wells is 2 to 5 inches with about 3 inches optimal, because packs much over 5 inches make development genuinely difficult; the development energy cannot reach the formation through that much gravel. Most state codes land in a 2 to 8 inch practical range. Finally, placement: A100-20 requires the pack to extend a minimum of 20 feet above the top of the screen to allow for settlement during development.
What to check before you order
• Verify the actual grade of the filter pack by requesting an updated sieve analysis from your filter pack provider. The sieve analysis is what matters, not the product label. If a product name say “#8”, for example, make sure you know what percentage of the filter pack passes each sieve size.
• Design pack thickness in the 3 to 5 inch range and treat 12 inches as the code ceiling it is, not a design goal.
• Heads up: AWWA has a revision of A100 in the works, and the announced changes include the pack to formation ratio and pack thickness provisions. We will cover the new edition when it publishes.
Sources:
• Roscoe Moss Company: Technical Memorandum 006-2: Gravel Pack Design
Industry Events
Groundwater Resources Association of California: 2026 Groundwater 101 Week
July 13-17, 2026; Virtual Attendance
Information and Registration: GRA: 2026 Groundwater 101 Week
American Ground Water Trust: New Mexico Water Well Workshop
July 16, 2026; Albuquerque, NM
Information and Registration: AGWT: NM Well Workshop
WateReuse Arizona: 2026 Arizona Water Reuse Symposium
July 19-21, 2026; Flagstaff, AZ
Information and Registration: WateReuse: Arizona Symposium
South Atlantic Jubilee
July 25-27, 2026; Myrtle Beach, SC
Information and Registration: South Atlantic Jubilee
NGWA: Groundwater Week 2026
December 8-10, 2026; Las Vegas, NV
Information and Registration: NGWA Groundwater Week 2026
If you have a conference, symposium, workshop, or water well related event that you would like mentioned, contact us at [email protected]
Work Hard. Work Smart. Stay Safe!
