Wetlands
Wetlands Presentations
Wetlands Presentations This is the first in a series of presentations discussing issues surrounding the Hogan/Pancost development in South Boulder. Versions of these presentations were given at the January 19th, 2012 Concept Plan Review at the City of Boulder Planning Board meeting. The presentations show the impacts on wetlands that excavation and ditch maintenance activities had in 2008.

Hogan/Pancost Wetlands - Part I
Hogan/Pancost Wetlands - Part II

Major Points

  • The wetlands on the site were heavily impacted by excavation events in February and May 2008, immediately prior to the wetlands delineation field work in September 2008.
  • The 2010 wetlands report, that was based on the 2008 field work, shows minimal wetlands on the west side and extensive wetlands on the east side.
  • Staff, 3rd party review and Planning Board accept the wetlands study. No one mentions the impacts from 2008.
  • Flood irrigation was stopped and the south lateral on the west side was lined in 2008 to eliminate ditch leakage.
  • Acting on a citizen request City staff, Army Core of Engineers and the developer's wetlands consultant visited the site in 2011
  • This fieldwork shows a doubling of wetlands on the west side and a major decrease of wetlands on the east side.
  • Change attributed by the developer to sprinkling practices on the CD Bodam property, an increase in precipitation since 2008 and the cessation of flood irrigation.

Documentation

Wetlands Change Explanation

There was a major change in the delineated wetland acreage between 2008 and 2011.


2008 Wetland Delineation


2011 Wetland Delineation

The following table shows the percent changes:

West SideEast Side
2008 Delineation:0.717 acres 1.622 acres
2011 Delineation: 1.69 acres 0.468
Increase:135%-71%

In the developer's October 4, 2011 letter to the City they explain this change:

Compared to the 2008 wetland study, this 2011 study shows an increase in the number and size of the wetlands on the West Parcel and a decrease in the size of the wetlands on the East Parcel. These changes are likely due to an increase of irrigation waters on the CD Bodam property to the south of the West Parcel augmented by higher 2011 seasonal precipitation levels. On the East Parcel, the wetlands have decreased in size, likely as the result of termination of flood irrigation in the fall of 2008. We anticipate finalizing the 2011 Wetland Delineation Report at the end of October.
The October 17, 2011 Concept Plan describes this irrigation as:
The sprinkle irrigation system sprays water across the south property line of the Hogan- Pancost property north of the lateral and moistens the soil through out the growing season.
The increase is attributed to sprinkling overspray from the south property and an increase of precipitation in 2011. The following table and chart shows the total yearly precipitation for the last 11 years. As can be seen 2011 shows no significant increase from the values over the prior years.

YearTotal Precipitation
200015.96
200118.28
200213.88
200322.12
200427.17
200517.42
200619.31
200717.13
200817.12
200922.19
201017.6
201118.38


2000-2011 Annual Precipitation


http://www.esrl.noaa.gov/psd/boulder/Boulder.mm.precip.html

The decrease of acreage on the East parcel is attributed to a cessation of flood irrigation in 2008. However, the flood irrigation has always occurred on the west side not the east side. The following image shows the extensive lateral ditches on the west side and the areas that were typically flooded.


Area ditches and past flood irrigation


Past conditions on West side


Typical current conditions on East side

Furthermore, as one long time resident of the area states:

I bike or walk by that property every day. The parcel on the east side of 55th has often been under water the last few years due to the Howard ditch overflowing.
To follow the developer's logic the West side saw a cessation of flood irrigation and a large increase in wetlands due to increased precipitation. The East side, which was never actively flood irrigated, sees a marked decrease in wetlands.

 

 

 

The views expressed on this web site are solely those of the author. If you have any concerns or comments or believe anything on this web site is inaccurate or in error please contact the author at jeff.mcwhirter -at- gmail.com