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  1. Drew08

    Structural definition for stormwater?

    The New York State Standards and Specifications for Erosion and Sediment Control has three sections dealing with E&S measures: http://www.dec.ny.gov/docs/water_pdf/bluebook.pdf Section 3 Vegetative Measures Section 4 Biotechnical Measures and Section 5 Structural Measures I think it is pretty...
  2. Drew08

    Please respond if you have comments

    Specifics of the original question, local requirement, and legal standing apart, it is an interesting philosophical question as to the point of the rule. One reason being that the municipal stormwater system is usually the downstream property. The stormwater system is not only the manholes and...
  3. Drew08

    Please respond if you have comments

    I've seen this a lot. Pre-development means pre-development. Not pre-your-development. The owner should address it the same way as if it was in fact a new development, with on-site storage, bioretention areas, etc. Just because the previous owner got away with not meeting the standard for...
  4. Drew08

    Here is a puzzle that I've worked a

    Here is a puzzle that I've worked at for a while with out much result. Take profile station-elevation data, in this case stream profile data cut from a less than perfect LiDAR source, and filter the data such that only local minimum ordinances are left resulting in a station-elevation series...
  5. Drew08

    Draining a Pipeline System

    Actually makes sense to me. With all sections equal in diameter, the system drains only as fast as gravity can pull the water out. Energy loss through any section is proportional to its length. However, when the middle section is smaller in diameter, water is being pulled through it faster...
  6. Drew08

    Relearning how to do storm and sanitary calculations for Subdivision.

    Free EPA SWMM is my favorite for culvert networks. Just saying...
  7. Drew08

    Using weighted Curve Numbers for Basin Routing

    I think the rule and TR-55 is more accurate than you give it credit. Albeit it is an oversimplification as most regulations are in order to be dummy-proof, and the reviewer doesn't know quite how to articulate it. TR-55 states: "The watersheds must be hydrologically homogeneous, that is...
  8. Drew08

    Season High Water Table - Florida

    You might have luck with the USGS groundwater monitoring sites: http://maps.waterdata.usgs.gov/mapper/index.html Look for a site screened in the surficial aquifer. There are a bunch in the Naples region. It would probably be best to find 3 or 4 that surround your property and take an average...
  9. Drew08

    Flow routing through multiple basins

    Will 4 feet of flow depth down a 4:1 slope result in an erosive velocity, headcut formation, and a breach of the spillway?
  10. Drew08

    "Engineers don't know everything - they figure things out"

    No central source. You would have to go to each states licensing authority and check if there is a licence option for SE, or Structural Engineer. I don't know the full list (CA and IL are the only ones I can name), but it is typically in states that have somewhat complicated building codes...
  11. Drew08

    "Engineers don't know everything - they figure things out"

    I agree with you on a basic level. The reason most people love engineering is the opportunity to do new things and work on new and different projects. Again, flip side, if you ever feel pressured to provide design services outside your comfort level, or told to stamp something you're not...
  12. Drew08

    "Engineers don't know everything - they figure things out"

    If the new task is in your area of expertise, and uses skills you already have mastered. i.e., If you are a geotechnical engineer and have mastered basic geotechnical principals, you may be able to successfully design a pipeline foundation even though you've never done that before. I would...
  13. Drew08

    Dam breach analysis

    For typical dam breaches the default is the free unsteady-state USACE HEC-RAS, there is a breach component to it. But, there are many other proprietary and free programs/methods you can use depending on the situation and purpose of the study, some simpler, some more complex.
  14. Drew08

    EXCEL - Sorting Column Data for Hyetograph

    You certainly can develop a hyetograph directly from an IDF curve, its called a frequency rainfall distribution, completely unrelated to the SCS distribution, and Trackfiend is on the right track, he just needs help working through excel functions, not the hydrology. The idea is to have the 1...
  15. Drew08

    HEC-HMS vs PondPack Difference in Peak Flow

    HEC-HMS takes the Lag Time as input. Not the Time of concentration. I don't know about PondPack. This could be the issue if PondPack takes Time of concentration and you entered the values identically.
  16. Drew08

    HEC-HMS Model

    What is more accurate depends on the layout of the site. How to include a impervious(%) area depends on if the impervious area is directly connected to the outlet. Meaning runoff from the impervious surface has no opportunity to infiltrate, such as parking lot runoff into a culvert system...
  17. Drew08

    Climate data - what metric describes "coldest temp. a few days in a row"?

    Not an official term, but I'd call it something similar to 7Q10 for low stream flows, like 7T10 meaning the 7-day average low temperature that has a 10-year return period or 10% annual chance of occurrence. Could be 3T2, 3-day average low temperature with a 2-year return period, or whatever...
  18. Drew08

    Comparability of Storm Recurrence Intervals of Differing Durations

    First, I don’t think it’s nonsensical to compare the two. For designing a pump-storage system (or just storage assuming pump failure), volume becomes much more important than peak discharge, and duration has to be very carefully selected. Consideration for this case would be based more on...
  19. Drew08

    SCS/NRCS unit hydrograph peak rate factor in design

    From a pessimist: I'm convinced that when it comes to written rules and how those rules are enforced, constancy trumps accuracy because constancy is defendable, and idiot-proof trumps all because, to be honest, not all engineers are created equal. Standard methods are in place because...
  20. Drew08

    Smart formulas preset spreadsheet?

    To do the F=ma example in four cells, three input cells a, m, F, and one output cell. Enter values in the two knowns, and a keyword like "solve" in the third. For something simple like this, a nested if statement would work in the output cell, like: = if (a = "solve",F/m,if(m = "solve"...

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