A New Flow Regime

The 400+ mile long Roanoke River winds its way through less populous areas of southern Virginia and northern North Carolina.  It’s a river, however, with a legendary striped bass fishery, much history, and a watershed area larger than the Cape Fear, the largest basin contained within North Carolina.  The creation of two reservoir’s on the Roanoke, Kerr Lake (1940’s) and Lake Gaston (1960’s), changed the River’s natural flow patterns and led to a new era of ‘managing’ the river for multiple purposes, though not necessarily strategically.

Recently, The Nature Conservancy completed an agreement with the Army Corps of Engineers who are charged with managing these lakes to meet the multiple use requirements of the lakes in addition to mimicking a more natural flow regime. The management will help better sustain fisheries and have the secondary benefits that include reducing downstream flooding frequency.

“We are the River” a recent video on the Roanoke, details water management along with the river’s history and the challenges it faces. Want to learn more? Check out the short film at http://www.tellyawards.com/winners/2018/non-broadcast/general-nature-wildlife/we-are-the-river/198653/

Kerr Lake State Park.

Report It!

One helpful aspect of the tech revolution is the ability to look up and learn a wealth of information on almost any place using web maps.  This technology connects people with places, helping to answer the important question of where.  NC’s Division of Water Resources has developed an application for reporting fish kills and algal blooms using a map interface.  This reporting application helps identify and locate disturbing problems impacting North Carolina’s water resources.

Next time you’re out enjoying our State and see a fish kill or algal bloom that needs follow up, report it!


DWRs Reporting Application

A Mountain Problem Too

In western North Carolina near the Tennessee border, Fontana Lake is an area not typically associated with algal blooms.  Unfortunately, the Lake is experiencing just that.

The blooms there were first reported in 2012 in the Tuckaseegee arm feeding the lake and began returning annually 2015. The blooms started out as bright green discolored water.  Later, the algal die off turned portions of the lake into a stinky mess of decaying organic matter.

Worse, according to the State’s NC Division of Water Resources, tests have shown the algae to have toxic Microcystis levels that pose a “moderate” health risk, curbing usage of the lake and threatening wildlife.

Historically, nutrient related water quality problems like this have been located in eastern North Carolina.  As the images below show, however, these problems have expanded across the State and demonstrate the need for a statewide solutions to this serious problem

Fontana Lake Algae. Source: NC DWR

P R3

An essential nutrient in the growth of plants, phosphorus (P) when found in excess, can runoff and contribute to algal blooms and fish kills.

NC boasts the largest integrated phosphate mine in the US located in Aurora NC. Worldwide, the phosphate mining industry is a $76 Billion industry.

Most mined phosphorus goes into making fertilizers. About 20% of applied phosphorus is taken up by plants leaving the remaining 80% available for runoff.

Planet Money recently produced a podcast on Phosphorus touching on its importance, scarcity, and market demand. It also talks about ways prolong it’s availability through recycling.

Turns out that phosphorus, while essential for plants, is also a recyclable element in human waste.  Coming up with a solution that keeps the excess P from entering the water while prolonging the availability of the nutrient is a win-win.  Applying the Reduce, Reuse, Recycle (R3) mentality to phosphorus may help in the solution to nutrient pollution

Fertilizer Label


20-Years of Water Quality

Organic Nitrogen Trends, 1997-2016. (Source: NC DWR)

A November presentation to the NC Environmental Management Commission gave a snapshot of what’s going on with water quality trends in the State from 1997 to 2016.  Statewide, Ambient Monitoring Stations, or sites where NC regularly monitors water quality, were examined to give both a spatial and temporal understanding of what’s happening in our waterways.

Examining Total Kjehldahl nitrogen (TKN), a pollutant that contributes to water quality impairments such as algal blooms, state analysis sees a troubling trend of increased TKN levels. That increase helped contribute to 7 additional assessment areas being included on the State’s impaired water list.  This trend has also been covered in a previous post.

The State report also finds increases in turbidity and fecal coliform bacteria impairments along with those to fish and bug communities.

While other report findings were not as bleak (decreases in some metals like copper and zinc), the overall picture is one that reminds state officials that more improvements are needed if we are going to take measurable strides in making state waters more fishable and swimmable.

Neuse Opening

What started back in 1997 has reached Falls Lake. Bruce Babbit, then Secretary of the Department of Interior, came to NC looking for a dam removal opportunity to commence a program that would stretch across the nation. Though only 7 feet tall, Quaker Neck Dam on the Neuse near Goldsboro was identified as the showcase Dam that would inaugurate this program and it was removed to much fanfare.

Was it a success?  According to US Fish and Wildlife Service research, Yes!  They found that, after removal of Quaker Neck Dam, eggs and larvae of both shad and striped bass moved upstream from Goldsboro all the way upstream to Milburnie Dam near Raleigh (https://www.fws.gov/raleigh/coastal/NeuseAnadromousHandout.pdf).

Fast forward to this week. After a long approval process, Milburnie Dam began being removedHaving seen the blockage this dam creates for spawning fish, I believe this is a good thing for the Neuse River. Fifteen miles of the river’s mainstem are now open to migrating fish and recreational uses of the river will be enhanced.

Though it took two decades to get to this point, it’s good to see the Neuse take a step toward a more natural state with the removal of Milburnie Dam.
Dam Removed!
Milburnie Dam (Before Removal)

The Jordan Game

Not the basketball player whose game was enjoyable to watch but the unnerving game being played with water supply for Triangle communities. This past spring, the NC leg passed Session Law 2017-57, a budget bill funding experimental technologies for reducing harmful effects of nutrient pollution in Jordan Lake, a drinking water source for the Triangle. The bill is being used to fund wide use of SePRO algaecides on the Lake in an attempt to control high algae levels.

The Army Corps of Engineers currently owns and operates Jordan Lake for multiple uses covered in a previous post.  The proposal from SePRO would require the dumping of tons of chemicals and other substances in the lake in an attempt to control algae. Given that the Lake is under Federal control, Corps approval is needed for this plan to make sure uses of the lake are not compromised.

Given that this technology is untried at this scale, the following are some concerns over it:

  • Would this project contribute to another impairment of Jordan Lake? Repeated application of tons of chemicals may adversely affect the biology of the Lake. One of the chemicals being proposed is Copper which, in excess concentrations, can be toxic to aquatic organisms.
  • Without the rule driven requirements to control nutrient pollution, how long would SePRO be funded to continue this project?
  • Could the treatment area be effectively expanded? The project is being tested on this most polluted arm of the lake at a cost of $1.3 million. If successful there, could it be attempted at other polluted areas of Jordan Lake.
  • Is the Lake a good candidate for this product?  The Lake is more shallow than areas where the SePRO chemical treatments have been effectively used.
Kayakers making good use of Jordan Lake.

Overall, there’s little evidence that this will be any different than the failed Solar Bee project. That is, taxpayer money being used to fund experimental technology but not supporting proven nutrient reduction measures. Actual lake clean up is needed so that we can rely on Jordan Lake for our long-term water supply needs.

In NC, Low-Flows Increasing

Detailed in a July 2017 news story, the occurrence of extreme low-flow conditions in NC piedmont streams is increasing.  The story is based on USGS research,  that looked at the 7-day, 10-year (7Q10, W7Q10) low-flow discharges.  The 7Q10 is the lowest average discharge over a period of one week with a recurrence interval of 10 years. The measure identifies rare and extreme events of low water flow in streams.

The USGS report summary findings for 7Q10 trends at 63 gages with 30 or more years of climate date include the following:

  • The 7Q10 discharges did not change for 3 sites,
  • 5 sites had increased discharges with a median of +13.2%;
  • 55 sites had decreased discharges with a median of -22%;
  • The median percentage change for all 63 stream gages was –18.4 percent.

Factors such as increased development, increased water withdrawals from agricultural, industrial, and municipal users, and erratic rainfall patterns contribute to the reduced flow critical for drinking water and dilution of pollutants.

Moderate Summer Flow on the Neuse allows for Kayaking.

Indeed, findings from UNC researcher Nathan Hall presented at this year’s WRRI conference pointed out that recent algal blooms in the middle Cape Fear River are directly tied to low-flow events.  Hall summarized the following:

  1. Recent, extreme, summertime low‐flow events provide sufficient light and travel times for algal bloom development.
  2. Stratification likely plays an important role in determining overall phytoplankton biomass and competitive dominance by positively buoyant cyanobacteria.
  3. Recent increase in blooms likely related to flow rather than increasing nutrient concentrations because nutrients are, and have been, replete for a long time.

What’s this all mean? Most importantly, our water is a finite resource that needs to be protected to insure that both human and natural uses are sustainable.  Water wars can be found throughout the US and given the trends found in this USGS research, we need mindful policies to insure they don’t happen here.


Flood Control

Eastern NC saw major flood events in October 2016 and April 2017.  The most recent storm was centered a little west of the catastrophic rain from Hurricane Matthew.  Flooding from both of these events, however, were able to be mitigated somewhat by the presence of Falls and Jordan Lake reservoirs in the Triangle.

Both Falls and Jordan reservoirs are manmade with construction beginning in the 1970’s. In the Triangle area, these lakes receive much attention for their ole of providing drinking water to the growing region.

The largest portion of these lakes storage, however, is dedicated to flood control.  This function was in the news recently as the Army Corp had to release higher volumes of water from Falls Lake to maintain the lake’s ability to provide flood storage. While these releases do have minor flooding impacts on those near the dam, they are not as severe or extreme as flooding that would have occurred had the dams not been built.  Plus, by freeing up more flood storage, they help to mitigate the chance of extreme flooding downstream.

Lake Allocations




% of Total Storage


% Total Storage

Flood Control 221,182 62.7% 538,400 71.5%
Water Supply 45,000 12.8% 45,800 6.1%
Low Flow Augmentation 61,322 17.4% 94,600 12.6%
Sediment 25,073 7.1% 74,700 9.9%
Total Storage 352,577 100.0% 753,500 100.0%
Source: Falls -http://epec.saw.usace.army.mil/fallpert.txt

Jordan- https://deq.nc.gov/about/divisions/water-resources/planning/basin-planning/map-page/cape-fear-river-basin-landing/jordan-lake-water-supply-allocation/jordan-lake-water-supply-allocation-background-info

Jordan Lake Water Storage Allocations


An Interesting Ride

For the second time in about 6 months, Crabtree Creek was in full usage of its floodplains as the Raleigh area received around 7 inches of rain over two days.

Heading down to the greenway along the Creek the week after the rain, we came across this indicator of urban flooding – plastic bags littering suspended tree branches.  It’s one indicator of the being in an urban watershed and the need to try to reduce the amount of plastics we use.

Urban Flooding Indicator

There were other indicators of flooding: washed out sections of greenway pavement, knocked down fencing, and muddy trails.  Remarkably, however, the undeveloped floodplains were functioning in the way that they should and infiltrating the floodwaters that had inundated the area. It was interesting to see these areas doing what they are supposed to given the major flooding a few days earlier.

Crabtree Creek gage during the near record flood earlier this year.