HSG classification for EnF-Entiat 1

[DPAJR]

Hi All,

Does anyone know the soil type for EnF-Entiat. The NRCS map unit description says it is sandy loam with moderately high capacity to transmit water (0.57 to 1.98 in/hr). Which would make it Soil Group A. However, it also says "Available Water Capacity Very Low (about 1.8 inches)". Which points to a higher runoff potential than most group A soils. Using a Runoff Curve Number from the table for a type A soil might result in a lower peak discharge than what would actually occur.

Entiat seems to be about the only soil type not shown in the soil types listed in Hydrocad.

Thanks,
dpajr

 

[Drew08]

The NRCS Soil Data Mart, RUSLE2 Related Attribute table for EnF in Chelan County Washington identifies Enf as HSG D.

In addition to the Ksat, and drainage class, HSG is also based on the depth to the most restrictive feature. According to the Map Unit Description, bed rock is located a mere 12 to 20 inches below the surface.

 

[DPAJR]

Thanks Drew08,

I used a CN of 80 for the Enf. It calculated out to 85 but the entire area is covered with thick weeds so I subtracted 5.

Just as an interesting aside a hundred year storm calculates out to 92 cfs in HEC-HMS. The owners have all this anecdotal information that no one has ever seen water running in the ravine. They will not be happy and will probably accuse me of making a mistake.

A check with the state climatologist got me 51 years of daily precipitation data in an Excel spreadsheet. It's rare to get over a half inch of precip in that area but the 100 year storm is 3 inches. Now that I have done the calc it's time to prepare for the real battle. The largerst storm in the last 51 years was 1.88 inches. That's why no one remembers any runoff.

dpajr

 

[DPAJR]

HI Drew,

Thanks for the info. I have been searcing the internet for a couple of hours now. I can't seen to find an HSG for Entiat. Lots of technical descriptions but no classification.

The NRCS web site says I have to go into my spam blocker and allow them to send me emails. I can't seem to figure out how to do that in Spyware Doctor.

Do you know of an official web site where I can fine the actual classification?

Thanks,
dpajr

 

[Drew08]

I like the NRCS soil data mart. You only need to supply an email to download data not to view data. You do need to turn off the pop-up blocker though.

http://soildatamart.nrcs.usda.gov/

Select state > county > survey area > Generate Reports (not download data).

Scroll down to and select EnF. In the drop down menu, select the report you want to view. HSG is in the RUSLE2 report. Other useful information is in the map unit description and, physical and engineering properties reports. And, select Generate Report (again, not download data). A PDF will Pop-up containing the selected report.

The NRCS Web Soil Survey has the same report functionality, except you need to visually find and outline an area of interest in an on-line map viewer. Then select the Soil Data Explorer Tab. You'll find a wealth of info including HSG that can be visually plotted or viewed in report fashion.

http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm

I only found EnF in Chelan County Washington WA607, but it may be in surrounding areas as well. If you navigated to a region or soil survey not containing EnF soils, you will not be given the option to view the EnF reports.