Monitoring the water balance of seepage lakes to track regional responses to an evolving climate

Understanding the causes of large fluctuations in lake water levels is important for adaptive resource management. The relatively simple water budgets of small seepage lakes make them potentially useful model systems, provided that key water balance components can be well constrained. Here, spatial variability in measured rates of evaporation (E) and precipitation (P) at the whole lake scale was investigated, and the effect on daily and seasonal water balance estimates was quantified. To estimate spatial variability, triplicate sensor platforms were deployed on and near an 18 ha seepage lake. Lake stage (S) was monitored at a single node in the lake. The water balance was closed by estimating net groundwater seepage (Gnet) analytically as Gnet = ∆S – (P – E). Instrumentation on a second seepage lake was maintained by citizen scientists to assess the potential for more widespread sensor deployments. Data were collected every 30-minutes for six months. The results indicate that low-cost sensor networks with single nodes to measure E, P and ∆S provide well-constrained water budgets at daily and seasonal time scales.

Water chemical properties of a lake originated from “Chandagan tal” lignite mining

We did hydrological survey of a lake which was originated with seepage water from a brown coal mine located in Murun soum, Khentii province. The objectives of this study were to determine water chemical properties and compare to standards and norms for water quality assessment and to know which propose we can use this seepage lake water. We took samples from the different depths of the lake. According to the Alekhin classification the lake water is included in the hydrocarbonate class and the sodium group, with first type water. Seeing water quality, it is salty or highly mineralized (mineralization is 1600 mg /L at 3 m depth), very hard (total hardness is 18.7 mg-eqv /L, and carbonate hardness is 12.8 mg-eqv /L) water. This lake water contains several macro and micro elements exceeding allowable concentration of drinking water guidelines. Because of high salinity it seems not appropriable for cropland watering, although all elements’ concentration within the allowable concentration list. The lake water is partially possible for aquaculture and livestock use, after other detailed toxicological assessments are made. Чандган тал хүрэн нүүрсний уурхайн шавхалтаас үүссэн нуурын усны химийн үзүүлэлтүүдийг судалсан дүн Бид Хэнтий аймгийн Мөрөн суманд орших хүрэн нүүрсний уурхайн шавхалтаас үүссэн нууранд гидрохимийн судалгаа хийсэн болно. Энэхүү судалгааны ажлын зорилго нь усны химийн шинж чанарыг тодорхойлох, усны чанарын үнэлгээний стандарт, нормтой харьцуулахаас гадна тухайн усыг ямар зориулалтаар ашиглаж болох талаар судалгааг хийж гүйцэтгэхэд оршино. Энэхүү нуур нь 6.3 га талбайг эзлэн оршиж гүн нь хамгийн гүн хэсэгтээ 5.7 м хүрч байсан ба 256374.85 м3 эзлэхүүнтэй байна. Үүсмэл нуурын ус нь байгалийн усны ангиллаар гидрокарбонатын ангийн, натрийн бүлгийн 1-р төрлийн ус байна. Чанарын хувьд давсархаг буюу их эрдэсжилттэй (эрдэсжилт нь 3 м гүндээ 1604 мг/л), маш хатуу (нийт хатуулаг нь 18.7 мг-экв/л, карбонатын хатуулаг нь 12.8 мг-экв/л) устай. Тухайн нуурын усанд агуулагдах Al, As, Be, Ca, Cd, Fe, Mg, Mn, Na, Ni, Pb, U, SO2 зэрэг элементүүд нь “Ундны ус. Эрүүл ахуйн шаардлага, чанар, аюулгүй байдлын үнэлгээ “MNS 0900:2018” стандартын зөвшөөрөгдөх дээд хэмжээг давсан үзүүлэлттэй байна. Эдгээр элементүүдээс хор аюулын зэргээр илүү As, U, Pb, Cd зэрэг хүнд металл 2-9 дахин давсан үзүүлэлттэй байв. Бидний судалсан нуурын усанд газар тариаланд хэрэглэж болох усанд байх элементүүдийн зөвшөөрөгдөх дээд хэмжээнээс давсан зүйлгүй боловч давсжилт өндөртэй учир хөрсийг давсжуулах эрсдэлтэй байж болох юм. Энэхүү нуурын усыг усан сангийн аж ахуй, мал аж ахуй эрхлэх зориулалтаар ашиглахаар бол хоруу чанарын судалгааг нарийн хийх хэрэгтэй юм. Түлхүүр үг: эрдэсжилт, хатуулаг, ундны ус, усны хэрэглээ

Response in the trophic state of stratified lakes to changes in hydrology and water level: potential effects of climate change

To determine how climate-induced changes in hydrology and water level may affect the trophic state (productivity) of stratified lakes, two relatively pristine dimictic temperate lakes in Wisconsin, USA, were examined. Both are closed-basin lakes that experience changes in water level and degradation in water quality during periods of high water. One, a seepage lake with no inlets or outlets, has a small drainage basin and hydrology dominated by precipitation and groundwater exchange causing small changes in water and phosphorus (P) loading, which resulted in small changes in water level, P concentrations, and productivity. The other, a terminal lake with inlets but no outlets, has a large drainage basin and hydrology dominated by runoff causing large changes in water and P loading, which resulted in large changes in water level, P concentrations, and productivity. Eutrophication models accurately predicted the effects of changes in hydrology, P loading, and water level on their trophic state. If climate changes, larger changes in hydrology and water levels than previously observed could occur. If this causes increased water and P loading, stratified (dimictic and monomictic) lakes are expected to experience higher water levels and become more eutrophic, especially those with large developed drainage basins.

Seasonal nitrogen dynamics in a seepage lake receiving high nitrogen loads

Studies on nitrogen dynamics in seepage lakes are seldom undertaken, yet our understanding of the complex pattern of the nitrogen (N) cycle is complicated by its temporal and spatial heterogeneity. This research investigated temporal variation in N concentration, considering different forms of N (NO3–, NO2–, NH4+, dissolved organic N, particulate organic N) in a Spanish flowthrough seepage lake (Colgada Lake) receiving high N loads. The study was based on monthly data collected over the period 2003–2005 from lake inputs and outputs, vertical profiles at a single representative site in the middle of the lake and fluxes of NH4+ and NO3– at the sediment–water interface. The distribution of total N (TN) inputs and outputs did not follow a clear temporal pattern. TN inputs varied from 27.70 to 125 tonnes N month–1, 75–84% of which is NO3–. Temporal variation of concentration profiles for different N forms measured showed significant differences owing to stratification. Ammonium always entered the sediment, whereas sediments acted as either a sink or source of NO3–. Fluctuation in N dynamics in this lake was more influenced by external factors, such as the input variability, than by the turnover of nitrogenous substances in the water body. Comparing seasonal N dynamics, there seems to be temporal differences between seepage lakes and drainage lakes. In seepage lakes, dissolved inorganic nitrogen (DIN) peaks were reached in early spring and after overturn, whereas in drainage lakes, the autumn minimum gradually increased to maxima in late winter and during the stratification period.