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Therein lies the rub, say scientists, who are concerned about lowering DO standards ÷ and the comparisons used by Tampa Bay Waterâs environmental consultant, Janicki Environmental, to support a change in the water quality standards.
The current requirement of 5 milligrams per liter (mg/l) of dissolved oxygen is based upon national standards, but DO typically drops as water temperatures rise. Tampa Bay Water has asked the FDEP to calculate an appropriate DO based upon local conditions with tiers reflecting short and long-term averages.
For example, one alternative criteria calls for no more than 30% of the river volume having a daytime DO of less than 2.89 mg/l for more than 36 days.
Janickiâs assessment used the Little Manatee River as a basis for comparison. But some agencies point out that half of the Little Manatee watershed is farmland, a key source of oxygen-robbing nutrients. Parts of the Little Manatee are already impaired because of low DO levels; using it as a basis for comparable standards is questionable.
Hillsborough County scientists also questioned Janickiâs conclusions on the effects of low oxygen on various species, drawn from a Chesapeake Bay study that did not account for the combined impact of high temperatures and low DO.
Whatâs Next?
ãWeâre not trying to lower water quality standards to do this project ÷ we want to set an appropriate standard and then be judged against that standard,ä said Paula Dye, project manager for Tampa Bay Water. ãIf we canât meet the right standards then weâll go back to our board of directors and recommend that they not do it.ä
FDEP will hold a public meeting in Tampa in late Spring or early Summer once they have analyzed the data and evaluated the criteria. If a change is proposed, a public hearing will be held as a potential precursor to a formal challenge.
If FDEP does not allow DO levels to be lowered, Tampa Bay Water must immediately begin considering other options to ensure that water supplies grow concurrently with the regionâs population. The upstream harvesting-downstream augmentation project was proposed to provide an additional 13 to 17 million gallons of water (mgd) per day to meet predicted needs through 2017.
However, given concerns about nutrient loadings and recognizing that the river will only be augmented during periods of already moderate to high flows, Tampa Bay Estuary Program senior scientist Holly Greening wonders if perhaps the river would be better off without any augmentation. ãI think we need to take a good look at what would happen if we allow increased withdrawals without demanding replacement,ä she said. ãIt may be a better solution than augmenting with the wastewater.ä
Downstream augmentation was selected as an alternative from a list of approximately 300 recommendations considered earlier this decade to increase water supplies by 2012, Dye said. ãI donât think taking more water without augmenting was ever considered.ä
Another option may be augmenting only the Tampa Bypass Canal, an artificial structure built in the 1960s to divert water and prevent flooding, but an additional source must still be found. ãTo get to the quantity we need to supply regional needs, we really need both systems,ä Dye said. ãWe could still get a portion from the canal, but the river is an important component of the plan.ä
A Letter of Response from Tampa Bay Water
Dear Editor,
Your recent article entitled "Hillsborough River Proposal Raises Red Flags" raised concerns for us at Tampa Bay Water, the agency that is studying the Downstream Augmentation Project.
First, the article stated that downstream augmentation would increase nutrient loadings in the Hillsborough River, proliferating the growth of algae and stressing marine life. I can assure you that Tampa Bay Water will not pursue this project if there will be algae growth or marine life problems. Further, the permitting agencies would not allow such consequences either. So this "red flag" is unfounded.
Secondly, the article implied that we would augment the river during summer months when the water is stagnant. This is not true. We would take river water for potable use and augment with reclaimed water only when the river flows are at least 65 million gallons per day (100 cubic feet per second) which is 10 times the current MFL for the river. In other words, this project would take water during high flows of the river, not when the river is stagnant. This "red flag" does not exist.
We appreciate the interest Bay Soundings has shown in this project and look forward to working with you on future stories as the project evolves. Know that Tampa Bay Water is committed to developing this project only if it we can maintain the environmental integrity of the Hillsborough River.
Sincerely,
Paula Dye
Chief Environmental Planner
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Proposed Minimum Flows Pose Life-Changing Choices For Lower Hillsborough River
By Phil Compton
Chair, Friends of the River, Inc.
It isnât often that you get to have a say in the future of a major natural resource. This year the quest for balance in the needs of man and the environment will be decided in Tampa: the future of the lower Hillsborough River, how much fresh water itâs allowed every day, how much dissolved oxygen we give its fish to breath, and how fresh and pure that water is. Will we allow the lower Hillsborough River to function naturally as an estuary for Tampa Bay, or condemn it to be degraded permanently as a dead-end canal?
For over 100 years the lower Hillsborough River has been dammed at Rowlett Park. Most of that time, plenty of water flowed over the dam, allowing it to fully function as a natural estuary. Not until the 1970s ö when Tampaâs growth coincided with a major drought ö did no fresh water flow downstream. In recent years, fresh water flowed only two months of the year. The entire lower river became as salty as the bay upriver to the dam, eliminating or damaging populations of many species as well as larval populations of other species.
Fortunately state law prohibits such environmental degradation, requiring the Southwest Florida Water Management District (SWFWMD) to set a minimum flow level (MFL) that optimizes natural conditions necessary for reproduction and survival of the full range of naturally occurring fish and invertebrates.
In 1998 the Tampa Bay National Estuary Programâs technical advisory group recommended a complete salinity gradient: a freshwater zone at the damâs base gradually becoming saltier as it mixes with the bayâs tides. But a politically expedient solution became necessary when then-Mayor Dick Greco told SWFWMD that none of the riverâs own fresh water was available for the minimum flow. (This was before Tampa Bay Water established plans to share resources within a regional supply system.)
SWFWMDâs 1999 MFL for the Lower Hillsborough was based on politics, not science: only 10 cubic feet per second of Sulphur Springs water is pumped upstream to the damâs base. This gives the river no net increase of fresh water, and fails to create a freshwater zone because Sulphur Springsâ mineral-laden water has an average salinity of 1.2 to 1.3 parts per thousand ö 3 to 4 times too salty to qualify as ãfresh water.ä
Only local citizens could oppose this deal, so Friends of the River (FOR) was formed to challenge SWFWMDâs rule. FOR, the city and SWFWMD agreed a new MFL would be set based on a 5-year scientific study. SWFWMDâs board receives the study this month, then the public will have two months to review and comment.
FOR, Sierra Club and the River Roundtable will host a Town Hall meeting on our choices for the future of our river and bay. It is critical that those who live, boat and fish on the river learn what science now knows about how much fresh water a river needs to function as a river, and that their voice be heard on how to provide this water.
WHEN: |
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Saturday, February 18 |
WHERE: |
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The historic Harbor Club, Nebraska Ave. @ the River, 915 E. Grant St., just east of Nebraska Ave., off Bird Street and I-275. |
WHEN: |
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10:00 am ö 12 noon |
For more information contact FOR at 813-841-3601, or www.friendsofhillsboroughriver.org |
Editorâs Note: While minimum flows are not directly related to downstream augmentation, both raise the question of what the lower Hillsborough River should become in the face of ongoing growth. There also is some concern that having the infrastructure in place for downstream augmentation during high river flows will make using treated wastewater an easy alternative to meeting increased MFLs
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