Ginger Creek Hydrilla Monitoring Protocols for Bid

Project Overview:

In October 2024, Hydrilla verticillata (Hydrilla) was detected for the second time in Illinois in

Ginger Creek Lake, a 26.5-acre lake in northeastern Illinois that is hydrologically part of the

Ginger Creek system in Oak Brook (DuPage County). See Appendix A, Figure 1 for a general map of the system.

During 2025, IL DNR and IL Hydrilla Task Force members conducted comprehensive fluridone-based herbicide treatments targeting Hydrilla and conducted follow-up monitoring of the Ginger

Creek system with strong first year success. IDNR is continuing herbicide treatments in 2026 and 2027 throughout the entire system, both in areas where hydrilla was detected and as preventative treatments in the downstream reaches to prevent the establishment of any fragments that may flush downstream.

Scope of Services

IL DNR seeks a qualified contractor to provide comprehensive monitoring efforts that complement the already established Hydrilla control herbicide program. The selected contractor will be responsible for three primary tasks over the course of this 2-year (2026 and 2027) contract, as well as documentation and reporting associated with each task:

1. Annual aquatic plant monitoring throughout the Ginger Creek system

2. Hydrilla tuber monitoring to determine the presence and density of tubers and turions if present

3. Inlet monitoring to verify no undetected upstream sources of Hydrilla exist.

Note on site access: The entirety of the Ginger Creek system is located on private property.

IDNR has secured access and treatment permissions from all relevant landowners along the main

Ginger Creek channel and will assist the selected contractor with access and coordination with landowners for the duration of this contract as needed.

Aquatic Plant Surveys

The contractor will conduct annual aquatic plant (macrophyte) monitoring across approximately

70 acres of waterbodies to assess Hydrilla treatment impacts and map infestation boundaries.

This survey shall be conducted once each year in 2026 and 2027 in the months of July, August, or September.

Methodology:

Surveys must utilize a rake-toss methodology with a pre-determined 30-meter grid of at least 314 sample sites that will be provided. At each designated sampling grid point, a plant rake must be tossed, allowed to sink, and dragged across the bottom toward the watercraft using an attached rope. After pulling the rake into the boat, plant coverage must be assessed for overall aquatic plant abundance, overall invasive plant species abundance, and presence/absence of native plant species. See Appendix A, Figure 3 for example of abundance ratings based on rake head fullness. Target invasive species that must be screened for include: Hydrilla, Brazilian Elodea, Pink Water Lily, and Curlyleaf Pondweed.

Data recording at each sampling site shall include:

• Depth at each sampling site

• Overall aquatic plant abundance at each site

• Invasive plant species present in the rake toss, noting the overall density/abundance and qualitative condition of each invasive plant species collected (D=Damaged/Decaying or

H=healthy).

• A record of site GPS if Hydrilla or Brazilian Elodea are encountered and it differs from the provided GPS location

• Photographic record of any Hydrilla or Brazilian Elodea encountered. Photos shall include a wider image of the entire plant and a close-up image of leaf/whorl detail.

• Documentation record of target invasive species observed within the immediate vicinity of the watercraft even if not captured in the rake toss

• Documentation of the presence/absence of other native species and relevant ecological comments.

Any plant specimens difficult to identify in the field can be bagged, labeled by site and date, properly stored, and identified using plant keys post survey.

If the contractor determines that additional sites may be worth sampling (for example, if they notice suspicious aquatic vegetation that is not at a pre-designated sampling site), they may conduct additional aquatic plant sampling, as long as the minimum of the pre-identified 314 sites are sampled.

Examples of datasheets and plant grid maps are provided in Appendix A, Figures 2 (datasheet) and 5-11 (plant grid maps and access notes). Final datasheets and grids shall be coordinated with the IL DNR and IL Hydrilla Task Force.

Access to the lakes for plant sampling will range from boat, canoe, or shoreline sampling. Some lakes will require a combination of these. See Table 1 for a breakdown of the number of survey sites at each location and site access information. There are no designated launches for motorized boats at any site, so consideration must be taken to avoid damaging landscaping at launch locations (i.e., prioritize the use of smaller, lightweight boats for site access). Landowners shall be notified prior to each site visit—IDNR will assist with this coordination.

Table 1: Waterbodies to be sampled and corresponding sampling points

Waterbody Acreage # of Plant Grid

Sites

Comments Access

Ginger Creek

Lake

26.5 126 Ginger Creek -

Google My Maps

Boat access

Butterfield

Country Club

6.9 31 Butterfield

Country Club -

Google My Maps

Canoe/From

Shore

Briarwood 19.5 91 Briarwood -

Google My Maps

Combo

Canoe/Boat possible

Oak Brook Park

District Pond 1

5.7 16 Oak Brook -

Google My Maps

Canoe

Lake Fred (West) 4 29 Lake Fred WEST

- Google My

Maps

Canoe

Lake Centennial

(East)

5 21 Lake

Centennial/Ed

EAST - Google

My Maps

Canoe

Additional notes on site access:

Ginger Creek Lake: accessible by small motorized boat, no developed launch

Butterfield Country Club: Accessible by walking shoreline (no boat or canoe)

Briarwood Lake: Accessible by small motorized boat & canoe. No developed launch. Some water control structures within the lake that prevent motorized boat access to all locations and will require use of canoe with up to six portages.

Lake Fred & Lake Centennial: Canoe access only. One portage between the two lakes.

Oak Brook Park District: Canoe only with up to two portages.

Tuber Monitoring

Hydrilla tubers can remain viable for 7-10 years in lake sediment. This project aims to establish a baseline to evaluate herbicide efficacy on the tuber bank. No tuber surveys have been conducted thus far in the system.

Methodology:

Tuber monitoring will be conducted once per year (twice total over the 2-year project) between late September and the end of November. Tuber monitoring will only take place in the 15 acres where hydrilla has already been detected in Ginger Creek Lake. Density of tubers in each https://www.google.com/maps/d/u/0/viewer?mid=1qkcqeQbBegHZry2LVZiFAutvI6OB6pQ&ll=41.83930093196753%2C-87.98215705997643&z=17 https://www.google.com/maps/d/u/0/viewer?mid=1qkcqeQbBegHZry2LVZiFAutvI6OB6pQ&ll=41.83930093196753%2C-87.98215705997643&z=17 https://www.google.com/maps/d/viewer?mid=1rgmo_3bKGlDAlzUtseXI6xdK1hL8lTI&ll=41.83631171339444%2C-87.97669952000001&z=17 https://www.google.com/maps/d/viewer?mid=1rgmo_3bKGlDAlzUtseXI6xdK1hL8lTI&ll=41.83631171339444%2C-87.97669952000001&z=17 https://www.google.com/maps/d/viewer?mid=1rgmo_3bKGlDAlzUtseXI6xdK1hL8lTI&ll=41.83631171339444%2C-87.97669952000001&z=17 https://www.google.com/maps/d/u/0/viewer?mid=1Urh5rB31NnFnTlA-HfKlHygZ6G5fZpE&ll=41.836589159331915%2C-87.964343835&z=16 https://www.google.com/maps/d/u/0/viewer?mid=1Urh5rB31NnFnTlA-HfKlHygZ6G5fZpE&ll=41.836589159331915%2C-87.964343835&z=16 https://www.google.com/maps/d/u/0/viewer?mid=1M9anfShWR5WAM1F2WYg2wmatH9PBuX0&ll=41.83905512597462%2C-87.95322749000002&z=18 https://www.google.com/maps/d/u/0/viewer?mid=1M9anfShWR5WAM1F2WYg2wmatH9PBuX0&ll=41.83905512597462%2C-87.95322749000002&z=18 https://www.google.com/maps/d/u/0/viewer?mid=1BJJo_pHeDghM2WAK_Pp1bfyjsoojiro&ll=41.83750249203826%2C-87.94720227&z=19 https://www.google.com/maps/d/u/0/viewer?mid=1BJJo_pHeDghM2WAK_Pp1bfyjsoojiro&ll=41.83750249203826%2C-87.94720227&z=19 https://www.google.com/maps/d/u/0/viewer?mid=1BJJo_pHeDghM2WAK_Pp1bfyjsoojiro&ll=41.83750249203826%2C-87.94720227&z=19 https://www.google.com/maps/d/u/0/viewer?mid=12PKV1BNd2vyRKPYqIO2EowTSaJ5RlMQ&ll=41.83673095735468%2C-87.944083405&z=19 https://www.google.com/maps/d/u/0/viewer?mid=12PKV1BNd2vyRKPYqIO2EowTSaJ5RlMQ&ll=41.83673095735468%2C-87.944083405&z=19 https://www.google.com/maps/d/u/0/viewer?mid=12PKV1BNd2vyRKPYqIO2EowTSaJ5RlMQ&ll=41.83673095735468%2C-87.944083405&z=19 https://www.google.com/maps/d/u/0/viewer?mid=12PKV1BNd2vyRKPYqIO2EowTSaJ5RlMQ&ll=41.83673095735468%2C-87.944083405&z=19 sediment core sampled will be used to assess the effectiveness of the herbicide treatment.

Sampling should be executed with a 10.2 cm (4 inch) diameter sediment core puller, specifications for which can be provided upon request and example images of which are provided in Appendix A, Figure 4. One sediment core will be collected per site and thoroughly sieved. All recovered tubers and turions will be collected and counted to determine density. GPS coordinates must be recorded and logged for every sediment core location.

Following North Carolina State’s protocols, a tiered sampling approach will be taken:

Tier 1: Pull an initial baseline of 30 cores. If 10 or more tubers are found across these 30 cores, sampling is complete

Tier 2: If less than 10 tubers are in the initial 30 cores, the contractor must increase the sample size to a total of 50 cores (collecting an additional 20 cores).

Data recording shall include:

• Number of tubers identified per core

• GPS coordinates of tuber location

See Appendix A/Figure 12 for a map of tuber sampling locations.

Inlet Surveys

To determine whether there is any source of Hydrilla upstream of Ginger Creek Lake, waterbodies upstream of the three inlets to Ginger Creek will be surveyed once during the 2-year project during the months of August or September. It is preferred that this take place during the first contract year in 2026 but surveys may also be conducted in 2027. In the upstream portion of the watershed there are three inlets into Ginger Creek and 1 inlet into Butterfield Country Club.

Waterbodies and creek areas in these upstream areas shall be assessed for presence/absence of

Hydrilla and Brazilian Elodea only. Sampling must be conducted at a minimum of 4 sites per waterbody or at one site every 300 feet of shoreline, whichever sampling site number/waterbody is larger. A minimum of 20 waterbodies should be assessed. Priority will be to waterbodies within a 0.5 mile of inlet to main water body. All permanent waterbodies directly upstream that are within 0.5 mile of the inlet shall be surveyed via rake-toss from shore. If a waterbody is not accessible (example: completely fenced off with no obvious access, or landowner permission cannot be obtained), sampling is not required. If sampling is not feasible due to these conditions, it should be noted on the data log.

GPS coordinates of each sampling location must be recorded and logged at each waterbody. A photographic record of any Hydrilla and/or Brazilian elodea encountered shall be made. Photos shall include a wider image of the entire plant and a close-up image of leaf/whorl detail.

See Appendix A/Figure 13 for maps highlighting potential waterbodies for sampling.

Decontamination

Contractors should be advised that Hydrilla is both a Federal Noxious Weed and an Illinois

Injurious Species. It can easily spread via a variety of mechanisms, including fragmentation, tubers, turions, and seeds. Contractors should take extreme care to avoid transferring any

Hydrilla between waterbodies on boats, sampling equipment, or personal gear. This is especially important if visiting multiple waterbodies in the same trip. Risks of spread can be minimized by working downstream to upstream and by decontaminating equipment using bleach or heated pressure washing between visiting different waterbodies.

Data Reporting

All data should be provided to IL DNR (raw data) and summarized in a brief report. Raw data should include all datasheets, whether in Excel format or other. A brief summary of approximately one page per project (aquatic plant surveys, tuber monitoring, and inlet surveys) describing the methodology, number of sites per waterbody sampled, total effort, and any notable results. Any included images, maps, figures, etc. may exceed the one page count. Photographic evidence of Hydrilla and/or Brazilian Elodea may be submitted in any format. Each photo file shall be named to include the waterbody name, site number, and date.

Final reports and data shall be submitted annually to IL DNR for review, no later than December of the calendar year of sampling. Reports from each of the three monitoring components may be submitted together, or separately. Any detections of Hydrilla or Brazilian Elodea during any monitoring efforts must be reported to IL DNR as soon as possible. For tuber monitoring, an estimated informal count of tubers shall be reported to IL DNR within a week of sampling.

Submittal Notes

While interested parties should submit an itemized bid for each of the three monitoring components, the final awardee will be responsible for all three monitoring components.

The interested parties should also submit a summary of qualifications of the project team and examples of at least two similar monitoring projects to confirm that they have the experience necessary to conduct this work.

Appendix A:

Figure 1: Ginger Creek Watershed

1. Ginger Creek Lake

2. Butterfield CC

3. Briarwood

4. Oak Brook Park

District Ponds

5. Lake Fred (West)

6. Lake Ed / Centennial

3 4

General direction of creek flow

Figure 2: Example of Required Data Sheet

Figure 3: Example of Abundance Ratings

Figure 4: Example of sediment corer and sieve

Images provided by Ohio State University

Figure 5: Aquatic Plant Sampling Sites at Ginger Creek Lake

Figure 6: Aquatic Plant Sampling Sites at Butterfield Country Club

Figure 7: Aquatic Plant Sampling Sites at Briarwood Lake

Figure 8: Aquatic Site Access Notes at Briarwood Lake

Figure 9: Aquatic Plant Sampling Sites at Oak Brook Park District

Figure 10: Aquatic Plant Sampling Sites at Lake Fred

Figure 11: Aquatic Plant Sampling Sites at Lake Centennial

Figure 12: Tuber Sampling Sites at Ginger Creek Lake

An initial 30 sediment cores will be sampled at the red (level D) and yellow (level C)-flagged sites If needed, an additional 20 cores will be sampled from among the green (level B) flagged sites

Figure 13: Inlet Monitoring Waterbodies

Figure 13A: Ginger Creek Watershed with inlets and upstream waterbodies Zone 1 and Zone 2 identified in following figures to show waterbody locations. Inlets are marked with red arrows.

Figure 13B: Zoomed in area of Zone 1 of Inlet to Ginger Creek north of I-88. Inlets are marked with red arrows.

Figure 13C: Zone 2 which includes two inlets to Ginger Creek and 1 inlet to Butterfield Country Club. Inlets are marked with red arrows.