Good Afternoon,
Anyone else get annoyed with the NWRFC’s water supply forecasts? Do they seem like they are all over the map at times? Contrast their numbers with ours, take the Clearwater for example:
Dark blue is Ansergy, teal is RFC’s. Ours is updated daily based upon a weighting of the precip and snow anomalies; also the Ansergy’ water supply is what we use in our own internal stream flow forecasts for the current water year. The above is for Jan-Jul, let’s take a look at the Lower Columbia (Jan-Jul):
Somewhat of a similar pattern but clearly the Ansergy forecasts are more stable. Her is the Apr-Sep:
We built this new report (replaces old water supply: Fundamentals / Hydro / Water Supply / Water Supply) because we lacked confidence in the NWRFC’s numbers. That said, it is the RFC’s numbers which will set flood control, not ours (too bad) but we believe that you can use ours to predict theirs. That flood control number, released around Jan 15, is hyper-critical in determining how Feb-March will play out, so being able to call that number well in advance is critical. So is managing your Q1/Q2/Q3 exposure if you set that exposure off of water supply.
Above are the charts, pretty simple and easy to run, what is more interesting, we think, is the summary table.
It is a busy table, let me explain the fields.
- Hub – all of the WECC is included, use the hub to filter out the basins of interest
- Basin – 31 basins reflecting 100% of the US WECC hdyro capacity
- MW – the cumulative downstream capacity – use this for ordering the most important to the top
- HC – one of our hydraulic capacity values; like MW, use it to group by size
- Source – either RFC (River Forecast Center) or ANS (Ansergy); there is no water supply forecast for the non-MidC, so these locations only have our numbers
- Period – there are three periods: Jan-Jul, Apr-Sep, and STP. The first two are self-explanatory, the STP requires a deeper dive, more on that later.
- CHG – this is the change from one week ago (W1) to the most recent (CUR): CUR- W1. Useful for finding the biggest movers.
- Periods – Cur=Current; D1 = yesterday; W1 = one week ago, etc
With a little filtering you can quickly get a nice view of what is happening with water supply:
We filtered on Period = STP and sorted descending on MW, and filtered on the RFC’s STP. The values reflect the % of normal (10 year average) using that week’s STP. Bear in mind these values reflect the 120 day STP period, they do not correspond to the traditional Jan-Jul/Apr-Sep. For today they would be Dec 12 to Apr 12.
Specific Station – Grand Coulee
In this view we simply filtered on Grand Coulee and we can see all six water supply forecasts. Note too that there is also an ANS STP forecast; this value reflects our pure runoff forecast for the STP period. In Coulee’s example, we are forecasting higher flows than the RFC for the STP period. However, Ansergy uses the STP from days 5-90, then we phase into our own numbers so by day 121 our water forecast is 100% Ansergy. Each day the runoff is recompiled and the best five years are selected by basin, so on occassion you may see jumps in our numbers as a basin switches to a new water year.
In this view we selected all hubs except Mid-C, Jan-Jul, and sorted descending on MW. Useful for getting a view of how the rest of the WECC is faring, though note the MW pales in comparison to the northwest, hence our hydro obsession with that hub.
Let us know if you’d like any special reports made, or some private training. And anyone that is a non-customer that would like to be walked through the report drop us a note.
Team Ansergy