Rocky Flats Site, Colorado, Tour – Walnut Creek Point of Compliance (WALPOC)

I'm standing at the confluence of three drainages. On the farthest is No Name Gulch, and that's actually its name. It comes from the present landfill, which is not presently active. It's just its name that it's the present landfill. It's a closed landfill. Flow in No Name Gulch comes down and is monitored by that water, that surface water monitoring station, GS-33, and it joins here with North Walnut Creek, which is the second drainage. It's hard to tell that they're ditches with all the growth, but that is North Walnut Creek, which comes from Pond A-4, and you can see the dam over towards past those cars. Also joining here is South Walnut Creek, which is the nearest of the three drainages, and it comes from South Walnut Creek, Pond B-5, and you can see the dam most distant with the white boxes on top of the crest of the dam. Those three drainages join here, and the flow exits through this flume and is monitored at this point of compliance, WALPOC, the Walnut Creek Point of Compliance, and we do, well, the way it works is the, because the flume has a known geometry and our automated equipment measures the depth, we can calculate how much flow, what the flow rate is going by, and collect the samples accordingly, and this is the equipment that we use for that. In this cabinet is the flow meter that tells the sampler how much flow is going by, and we've programmed the sampler to collect a small, what's called an aliquot, a small grab, small volume of water every so often, and that so often varies depending on the location, how much water it typically gets over its history, as well as the season. In the spring we get higher flows, and in the fall and winter we get lower flows, and the quality of the water changes as well. So what you might do, or you might have done in the, in decades past, was a surface water monitoring regime would be organized around somebody going to a stream with some bottles, and reaching down into the surface water and filling the bottles that quarter. We do something that's much more robust and much better data. We do what's called flow-paced monitoring. This is all automated, autonomous, we can monitor it from our office via telemetry, and this is the telemetry antenna here. Like all other powered equipment, it's operated off battery and solar, just like this is, and it's an elegant system. You get so much better data than just dipping bottles in the stream, and as you can see, this particular location is dry now. It tends to be dry from sometime in June until maybe February or March. There's not a lot of flow in Walnut Creek. Woman Creek is, has more flow, but this goes to show that these are ephemeral streams. There's not a lot of water at Rocky Flats. It's a semi-arid environment, and so when this is flowing, we're getting samples. When it's not flowing, these are waiting for the next flow. We don't turn them off. We don't change anything. The pace is set, is left alone with at whatever it was when this sample was begun, and again, Rocky Flats is not a source of drinking water, either surface water or the ground water at Rocky Flats is not a source of the drinking water, which is a good thing right now because there's none to be had anyway. It's all dry. I mentioned that the analytes here include plutonium, americium, uranium, and nitrate, and I should point out that americium is what is known as a daughter product of plutonium. The water, once it leaves here, it goes, it used to go to a reservoir called Great Western Reservoir, which was a drinking water resource for Broomfield. It was, but since the 90s, that Great Western Reservoir has been bypassed, 90s or early 2000s, and now the city and county of Broomfield have the choice of either putting the water into Great Western Reservoir and using it for things like watering their golf courses and such, or letting the water in Walnut Creek bypass Great Western Reservoir and go around it. But either way, Great Western Reservoir water isn't used for drinking water, last that we've been told. If conditions here, chemical conditions from our analytical data were to trigger, were to exceed the standard, the RFLMA standard, Rocky Flats Legacy Management Agreement standard, for any of those analytes, we have a 12-month and a 30-day average that we assess the data for. And if we, this is all spelled out in the Rocky Flats Legacy Management Agreement, we have decision flow charts that say what to do with the data. And at a point where we have an exceedance condition, we call it a reportable condition once it meets the criteria. And at that point, we will have informed the state of Colorado, the Colorado Department of Public Health and Environment, as well as the U.S. Environmental Protection Agency, and we have what's called a consultation. That's where DOE, CDPHE, or the state of Colorado, and EPA all get together, talk about the conditions, talk about what might have caused those conditions, whether it's flow rates being unusual or what have you, and then what the path forward should be, whether there should be an action to address the conditions that have been observed here. So that's the way the, that's why points of compliance are so important. The farther upstream, there are locations called points of evaluation, which are also defined with reportable conditions, but they're not, it's not nearly as critical as a point of compliance because this, this is, remedy protectiveness is what these are focused on.