**[Topic List:]{.underline}**

1.  Ski Run Stormfilter Vault Report -- Nicole Beck

2.  Ground Water Nutrient Loading to Nearshore -- Jim Thomas

3.  Preview of Water Quality Project Inventory -- Chad Praul

**[Topic Summaries:]{.underline}**

> **Ski Run Stormfilter Vault Report -- Nicole Beck**
>
>  
>
> The Stormfilter system is comprised of 50 perlite / zeolite filter
> cartridges enclosed in a concrete vault located at Ski Run marina in
> South Lake Tahoe.  2^nd^ Nature Inc was contracted to provide data
> analysis and a final report in 2004.  The first observation from the
> data was that the vault was retaining a small portion of the flow
> volume in the cartridge bay.  2^nd^ Nature also noted that lab results
> indicated that a couple of the traditionally dissolved analyses were
> performed on samples that were never filtered.  This underscored the
> importance of clear communication with lab staff on analysis
> techniques and proper communication with labs as some have different
> protocols and guidelines for analysis depending on what the sample is
> looking for.  For these reasons most data gathered in Lake Tahoe is
> incomparable to one another because of inconsistencies in analysis. 
> This also highlights the need for standardization of protocols and a
> fluid, consistent method for analysis.  However, constituents in this
> study are still valid in calculating removal effectiveness of the
> vault because they were consistently analyzed within the study.
>
>  
>
> Results showed that TSS removal effectiveness averaged 60% (except for
> the first two events after installation) and TP removal effectiveness
> averaged 44%.  The results showed lower effectiveness levels for
> dissolved nutrients- ranging from 37% to -32%.  Given the 18% load
> reduction due solely to volume retention, these numbers were not
> inspiring to the analysis team, but acceptable.  Field personnel
> suspect that negative efficiencies for Nitrite arise from chemical
> reactions taking place in the stagnant water retained between events. 
> 2^nd^ Nature made several recommendations including use of pre-project
> monitoring whenever feasible, reducing volume retained between events
> through proper installation and post-construction cleaning of vaults. 
> Contact Russ Wigart <rwigart@ci.south-lake-tahoe.ca.us> or Nicole Beck
> <nbeck@2ndnatureinc.com> for additional information. (Provided by Russ
> Wigart)

**Ground Water Nutrient Loading to Nearshore -- Jim Thomas**

Jim presented a pilot study that was intended to design a method for
determining the flux of groundwater and its nutrient load to the lake.
This work is important because previous estimates have been made by
calculating the difference between the water inputs and outflows of the
lake. The team also evaluated the nutrient load from one area of the
lake that had significant turbidity (and chlorophyll) but no significant
surface water inflow. The team drilled a series of groundwater wells in
the Kings Beach area and used them to calculate nutrient loads from this
area. They concluded that their method provided an adequate method for
determining the GW nutrient loads and calculated nutrient loading values
(for Kings Beach) of TN=850 kg/yr. and TP=31 kg/yr. Their research
further noted that the GW nitrogen comes from naturally occurring
organic matter, not from atmospheric inputs or synthetic fertilizer.

Jim also briefly mentioned additional work he is producing in
collaboration with Alan Heyvaert and Phil Bachand. The team is
characterizing the sorption capabilities of Tahoe soils, below
infiltration basins. This research should provide additional information
about the movement rates of phosphorous fronts towards the lake and into
ground water. The LTIMP Chair will invite the research team for a
complete presentation at an upcoming meeting. For additional information
contact <jthomas@dri.edu>.

**Preview of the Water Quality Project Inventory -- Chad Praul**

The Inventory has been a collaborative effort between the TMDL, NTCD,
USFS, and NDEP that intends to provide a system to inventory all water
quality projects completed at Lake Tahoe. This system is composed of a
Microsoft Access database and ArcView GIS map, linked by a custom VBA
script. The Inventory currently contains 132 projects comprised of about
1080 BMPs.

The database can be analyzed to total BMPs for the whole Basin, by
State, by year of implementation, or by Implementer. An example of the
results available from the database: Nevada has installed 3 times more
stormwater vaults than California, while California has 11 times more
stormwater basin volume than Nevada. These differences may illustrate
differences in terrain or differences in treatment strategies.

The GIS shows size and location of projects (not individual BMPs) and
can also illustrate interesting facts about current implementation. The
project areas can be added to estimate that 5% of the Lake Tahoe
watershed area has been "treated," 46% of roads have been "treated," and
42% of urban area has been "treated." The GIS can also calculate these
values for each of the 64 priority watersheds that drain to the lake.

The Inventory has taken data stored in many formats/locations and
converted it into easily accessible knowledge for Basin management. It
can be used for modeling the effects of BMPs on our watershed, as a
guide to maintenance of stormwater infrastructure and to report progress
of programs like the EIP.

The Inventory is designed to be used by non-technical users and is
available for download at
[www.ntcd.org/documents.htm](http://www.ntcd.org/documents.htm). The
downloaded .exe file will place all required data files in the
appropriate folders of your computer, however the Inventory requires
users to have Microsoft Access and ArcView 9 to run. Comments on data
quality and data gaps are welcome. Please contact <cpraul@ntcd.org>.

In Attendance:

Nancy Alvarez, USGS\*

Nicole Beck, 2^nd^ Nature

Robert Erlich, Lahontan

Mark Gookin, Wood Rodgers

Jenna Greene, USGS

Melanie Greene, Parsons

Christine Kirick, K/J Consultants

Alfred Knotts, EDOT

Kevin Murphy, Sac. State

Chad Praul, NTCD\*

Jenifer Quickel, EDOT\*

Andy Smith, WET Lab\*

Carl Thodal, USGS

Jim Thomas, DRI

Adrian Tieslau, Tieslau Enginering

Matt Vitale, NTCD\*

Next Agenda: