Thursday, June 14, 2012

Another Gem From Hruby

Much of the information, data, and reasoning that comes from the "experts" associated with the CAOs is embarrassingly poor. The emails below from Tom Hruby are about as bad as the letter he and Erik Stockdale co-authored to the Council on February 4, 2011. In that letter, I feel they demonstrated their complete ignorance of environmental risk. Their explanations appeared to confuse environmental risk with Type 1 and Type 2 error. I can only conclude that they have no idea that error, risk, uncertainty, and level of concern are all different concepts. To me, it's astonishing that they have their jobs without having a fundamental grasp of the differences among those concepts, much less be qualified to speak to the merits of statistical papers like Mayer.

At some point, the TH will post the Stockdale/Hruby 2011 letter and dismantle its reasoning. For now, have a look at the more recent Hruby missive below. It's hard to know where to begin commentary because it is just so awful, but maybe the best approach is to provide a few overall observations.

For Hruby, it seems the nitrogen cycle isn't a cycle. He only acknowledges nitrogen sources, but not denitrification.  He doesn't recognize that grasses (including corn) are heavy nitrogen users, and that's why people fertilize grass in the first place, so as to provide the added nitrogen that grasses demand.  Anyone who has ever had a compost pile knows that grass is almost pure nitrogen. And I don't know anyone in the islands who is even a moderate user of fertilizers, except perhaps the golf courses. Also, I don't think I've ever seen enough corn on the islands in one spot to qualify as a corn field either.

Hruby apparently is afraid of horse poop too, not realizing that the nitrogen in the poop is used by the grasses that get pooped on. The juxtaposition of his "grasses need nitrogen" point with his "manure has nitrogen" point shows no appreciation that the two competing processes might offset one another and be in balance here in the islands. Heck, with the surfeit of unfertilized hay that we grow, I would venture to guess that we might even suffer from general nitrogen deficiency and need more horse manure to be in balance.

The more these guys talk, the more it seems like we live in Bushwood Country Club and we're trapped in the movie Caddyshack.  Maybe given the leading role of Dr. Adamus, we should refer to it as Addyshack? How long before the experts recommend that we ban Baby Ruth bars?

I particularly enjoy how Dr. Hruby cites Europe and Australia when addressing Patty Miller's question about sources specific to San Juan County.

From: Patty Miller [] 
Sent: Sunday, June 03, 2012 9:35 PM
To: Shireene Hale; Ingrid Gabriel;;;;;
Subject: FW: Our discussions regarding pollutants coming into wetlands


I apologize for not forwarding this to you all earlier.

Thanks, Patty

From: Hruby, Tom (ECY) [mailto:thru461@ECY.WA.GOV]
Sent: Friday, May 18, 2012 9:36 AM
To: Patty Miller
Cc: Stockdale, Erik (ECY)
Subject: Our discussions regarding pollutants coming into wetlands

Dear Patty, 

I would like to summarize our conversations and my e-mails from yesterday into one to make it easier for you to follow my thoughts.  Please dis-regard the e-mails I sent yesterday, especially the first one that had an error in the math.

As I understand it from our conversations, you are concerned about three major issues (and please correct me if I am wrong):

1.       Do the articles referenced in the Mayer paper address the pollutants commonly generated in the dominant land uses of San Juan County?  Since most land uses in the non-urban areas do not generate toxic or hazardous materials, the removal of these compounds by the buffer is not a significant issue. 

2.       Were the amounts of pollutants used to calculate the removal rates in the articles reviewed appropriate for the amounts that might be found coming from the dominant land uses in SJ County?  

3.       Do we need to have a 75-80% removal of pollutants in the buffer if the amount of pollutants coming in is very low in the first place. Could we get by with a lower % removal because the amount coming through the buffer was so low? 

My analysis of your questions:

1.       Yes, the Mayer article does address pollutants generated by the rural land uses in SJC.  The Mayer article reviewed the literature on the removal of nitrogen by buffers.  First, when scientists talk about pollution from nitrogen we do not mean nitrogen gas but rather the different nitrogen compounds that act as fertilizers for both terrestrial and aquatic plants.  Excessive amounts of "nitrogen" cause eutrophication in wetlands, streams, ponds, and lakes.  The BAS report for SJC mentioned that nitrogen removal could be used as a surrogate for the removal other toxic pollutants and I think this is where it became confusing.  The major pollutant coming from the  rural and agricultural land uses common on the islands is nitrogen in form of fertilizers and ammonia and nitrate in animal wastes. Since the Mayer paper reviewed only the articles on nitrogen removal it is appropriate to use it for SJC.  If the lands uses in SJC do not generate toxic materials then we do not have to assume that the removal nitrogen can be used as a surrogate for the removal of toxic pollutants as well.  It becomes a moot point.  In urban and suburban areas of the county however, it is an issue because of the application of herbicides and pesticides used in gardening and landscaping. 

I should mention however, that there is one other pollutant coming from rural land uses that can be an issue.  This is pathogens (coliform bacteria and viruses) from animal wastes.  This is not considered an "toxic" material but it is a pollutant.  Pathogens by themselves have little impact on the functions of a wetland, but they do become an issue if the aquatic resource downstream is a source of drinking water or recreation.  Buffers can remove pathogens before they reach aquatic resources. 

2.    Most of the 88 articles used by Meyer to develop his model of nitrogen removal measured nitrogen removal in the field under actual conditions.  The studies were done throughout the country and in Europe and Australia.  The sources of nitrogen to the buffer zones therefore represent a wide range of different land uses that generate different amounts of nitrogen.  Some of the studies were done in forested system where very little nitrogen is released and some were next to pastures and cattle feedlots where the amounts (called the "loading rate") were extremely high. For example, one article (Hubbard and Lowrance 1997) looked at the effect different forest practices had on nitrate removal in buffers while another (Young and others 1980) looked at nitrate removal in buffers where the runoff came from feedlots.   

My conclusion is that the amount of nitrogen coming from the rural land uses in SJC fall within the amounts that were used to develop the Meyer's model of % removal. I did a quick search of how much nitrogen is applied in the land uses most commonly used for the buffer studies (agriculture, urban, residential)

For agriculture, corn is one of the most nitrogen demanding crops and it requires about 100lbs of nitrogen per acre per year.  Most crops require 50 - 100lbs/acre.  Note: nitrogen loading rates are measured as lbs of "atomic" nitrogen per acre.  For example there is only 1 lbs of nitrogen in 6 lbs of sodium nitrate, the rest consists of sodium and oxygen.   

         For residential lawns, the recommended amount is about 40-50 lbs nitrogen/acre per year thought most people apply more. 

         For pasture grasses it is about 60-80 lbs N/acre/year 

I believe that the biggest source of nitrogen in the rural areas of  SJC would be livestock of one type or another (horses, cattle, sheep, and even the camel on San Juan Island).  The amount of nitrogen coming from livestock in the county can fall within the range found for other land uses.  For example, a horse produces 9.1 tons of manure per year (see attached report).  Typically a ton of horse manure will contain 11 lbs of nitrogen so one horse will produce 100 lbs of nitrogen per year.  If that horse is confined to one acre the "loading rate" for nitrogen is similar to the highest level that is applied in agriculture.  If that one horse is pastured on 5 acres the loading rate is still 20lbs/acre/year.

3.    The one question I cannot answer is "how much removal is enough?"
If a rural land use generate 20lbs of nitrogen per acre per year is it adequate to remove 50% of this in the buffer or do we need to remove 80% to avoid impacts to the water quality in the wetland?    None of the articles cited by Mayer address this question and I have not been able to find any published research on this subject.  There is much research on eutrophication lakes caused by fertilizers, but none that I have found on eutrophication in wetlands.   The decision then becomes one of policy.  How much risk we are willing to accept?  We can be pretty sure that there will be little risk that the wetland becomes eutrophic if we remove 90 - 100% of the nitrogen going into it.  Removing only 80% increases the risk, and this goes even higher if we remove only  50% of the nitrogen coming in.  As you mentioned it may be worthwhile exploring buffer regulations based on the density of livestock upslope of the wetland rather than the size of the lot when addressing water quality. 


Tom Hruby, PhD, PWS
Senior Ecologist
Washington State Department of Ecology
PO Box 47600
Olympia WA  98504
(360) 407-7274 <>


  1. 1) I see that Patty is emailing the entire County Council there, on a weekend, presumably not during an open public meeting.

    2) Has Hruby calculated the nitrate generation from our livestock, and compared that to the load produced by our incredible deer population?

  2. Totally off topic....
    Did anyone hear that Vivian Burien, (the one who wrote a harsh critcism of us) is now being looked at for code violations for illegal construction??
    These rules are for everyone else, if you are a steward of the land, then you must get to decide which rules to follow.

  3. Let me try to answer Councilperson Miller's questions.
    1. No.
    2. No.
    3. No. Yes.

  4. Patty, can you see the door closing in on you. You have horse's and most of your property is a wetland. Thanks for supporting the rest of us.