**4. Discussion**

**140** Ecological changes of natural ecosystems were widely studied and documented. Nevertheless, cases such as Lake Kinneret-River Jordan ecosystem, which is strongly

**141**

were enhanced [7].

change?

**4.1 Water level and lake shrinkage**

*The Synergistic Impact of Climate Change and Anthropogenic Management on the Lake…*

affected by anthropogenic intervention, are a typical issue being under crucial scientific and practical research. This is aimed at both prevention of natural and the human society benefits. The Kinneret-River Jordan ecosystem was under complete natural impact until the early 1930s of the previous century, while later on the "Anthropocene Era" of this system was started [5] accompanied by natural climate change. The latest periodical season (1970–2018) was especially a very sensitive factor of significant impact on this system due to two major constrains: (1) water consumption and agricultural development in the watershed and (2) lake water supply. The major changes of regional climate change and the modifications within the Lake Kinneret Limnological trait are briefly presented: elevation of air temperature and Lake Kinneret water, decline of precipitation, agricultural and hydrological management of the Hula Valley land, decline of lake water level, reduced input loads of nitrogen and phosphorus accompanied by reduction of nitrogen and a slight elevation of phosphorus in the Kinneret Epilimnion, dominance replacement of Peridinium by cyanobacteria, chlorophytes, and diatoms. The tentative objective of this paper is aimed at an answer to the question: why and how were those changes developed? It was previously documented [6] that Nitrogen sources for Lake Kinneret are mostly external and mostly effective is nitrate from the Hula Valley Peat soil degradation and fishponds and domestic sewage. Therefore, after removal of sewage and restriction of fishponds, input loads of organic nitrogen were reduced significantly and the supply of nitrate is primarily precipitationdependent. Nevertheless, input loads of phosphorus from the watershed were reduced but P availability for the Lake Kinneret biota was slightly enhanced due to internal flux from the sediments and dust storm deposition. The dynamic changes of Phytoplankton composition in Lake Kinneret followed the nutrient alterations: the nitrogen consumer Peridinium was declined and cyanobacterial nitrogen fixers

A disputable issue was highlighted: agricultural water consumption or climate

Agricultural population in the "Upper Galilee" region (Upper Jordan River Watershed) was initiated during the early 1920s. From the very beginning, water supply for agricultural development was in the past and presently continues to be a major national concern. Nevertheless, the upper Jordan Watershed headwaters are the major source for the Lake Kinneret water budget but also for agricultural consumption. The multipurpose services of the Kinneret ecosystem are aimed at water supply, fishery, recreation, and tourism. Kinneret is the only natural freshwater lake in Israel, and environmental and water quality protection is essential. Moreover, water sharing is crucial and precautionary nationally and internationally guaranteed. Availability of preferential pathways in the undergrounds of the Hula Valley for subterranean water migration (obviously gravitating) is not an imaginary black hole but integrated component of the Hula Hydrological system. Evaporation is supposed to be reduced by enhancement of vegetation cover (Karacus 2019; [8–12]). The Hula Project Monitor Data Base documented annual 1376 mm with variations of 10% during the last 10 years and averaged as 1401 mm/y. This record is based on climatological parameters (Penman-Monteith equation). Multi-annual record (1960–2018) indicates no significant change in the vegetation cover in the Hula Valley region except the seasonality of crop cycling. The ET capacities were, therefore, potentially stable more or less unless climate conditions changed. That is because ET records in the Hula Valley (Hula Project–Migal Data Base) are mostly climatologically dependent (Penman-Monteith formula). Wine [13] and Wine et al. [5] documented the absence of significant climate change conditions in the Upper

*DOI: http://dx.doi.org/10.5772/intechopen.86512*

*The Synergistic Impact of Climate Change and Anthropogenic Management on the Lake… DOI: http://dx.doi.org/10.5772/intechopen.86512*

affected by anthropogenic intervention, are a typical issue being under crucial scientific and practical research. This is aimed at both prevention of natural and the human society benefits. The Kinneret-River Jordan ecosystem was under complete natural impact until the early 1930s of the previous century, while later on the "Anthropocene Era" of this system was started [5] accompanied by natural climate change. The latest periodical season (1970–2018) was especially a very sensitive factor of significant impact on this system due to two major constrains: (1) water consumption and agricultural development in the watershed and (2) lake water supply. The major changes of regional climate change and the modifications within the Lake Kinneret Limnological trait are briefly presented: elevation of air temperature and Lake Kinneret water, decline of precipitation, agricultural and hydrological management of the Hula Valley land, decline of lake water level, reduced input loads of nitrogen and phosphorus accompanied by reduction of nitrogen and a slight elevation of phosphorus in the Kinneret Epilimnion, dominance replacement of Peridinium by cyanobacteria, chlorophytes, and diatoms. The tentative objective of this paper is aimed at an answer to the question: why and how were those changes developed? It was previously documented [6] that Nitrogen sources for Lake Kinneret are mostly external and mostly effective is nitrate from the Hula Valley Peat soil degradation and fishponds and domestic sewage. Therefore, after removal of sewage and restriction of fishponds, input loads of organic nitrogen were reduced significantly and the supply of nitrate is primarily precipitationdependent. Nevertheless, input loads of phosphorus from the watershed were reduced but P availability for the Lake Kinneret biota was slightly enhanced due to internal flux from the sediments and dust storm deposition. The dynamic changes of Phytoplankton composition in Lake Kinneret followed the nutrient alterations: the nitrogen consumer Peridinium was declined and cyanobacterial nitrogen fixers were enhanced [7].

### **4.1 Water level and lake shrinkage**

A disputable issue was highlighted: agricultural water consumption or climate change?

Agricultural population in the "Upper Galilee" region (Upper Jordan River Watershed) was initiated during the early 1920s. From the very beginning, water supply for agricultural development was in the past and presently continues to be a major national concern. Nevertheless, the upper Jordan Watershed headwaters are the major source for the Lake Kinneret water budget but also for agricultural consumption. The multipurpose services of the Kinneret ecosystem are aimed at water supply, fishery, recreation, and tourism. Kinneret is the only natural freshwater lake in Israel, and environmental and water quality protection is essential. Moreover, water sharing is crucial and precautionary nationally and internationally guaranteed. Availability of preferential pathways in the undergrounds of the Hula Valley for subterranean water migration (obviously gravitating) is not an imaginary black hole but integrated component of the Hula Hydrological system. Evaporation is supposed to be reduced by enhancement of vegetation cover (Karacus 2019; [8–12]). The Hula Project Monitor Data Base documented annual 1376 mm with variations of 10% during the last 10 years and averaged as 1401 mm/y. This record is based on climatological parameters (Penman-Monteith equation). Multi-annual record (1960–2018) indicates no significant change in the vegetation cover in the Hula Valley region except the seasonality of crop cycling. The ET capacities were, therefore, potentially stable more or less unless climate conditions changed. That is because ET records in the Hula Valley (Hula Project–Migal Data Base) are mostly climatologically dependent (Penman-Monteith formula). Wine [13] and Wine et al. [5] documented the absence of significant climate change conditions in the Upper

*Sustainability Assessment at the 21st Century*

**140**

**4. Discussion**

*biomass (g(ww)/m<sup>2</sup>*

**Figure 20.**

**Figure 19.**

*Kinneret during 1969–2002.*

Ecological changes of natural ecosystems were widely studied and documented. Nevertheless, cases such as Lake Kinneret-River Jordan ecosystem, which is strongly

*Linear regression between multiannual averages of epilimnetic TN concentrations (ppm) and Peridinium* 

*) in Lake Kinneret during 1969–2001.*

*Temporal trend of changes (LOWESS 0.8) of monthly means of the biomass (g(ww)/m2*

*(upper left), cyanobacteria (upper right), diatoms (lower left), and Pyrrhophyta (lower right) in Lake* 

*) of chlorophyta* 

Jordan watershed. Givati [1] approximated an increase of 40 mcm/y consumption of Kinneret Headwaters.

Water legislative consumption inspected by the "Water Authority" was significantly reduced from >100 to 68 mcm/y at present implementation. Confirmed information documented restriction from 200 to 68 mcm/y. Conclusively, climate change, precipitation decline, and restricted legislative allocation essentially make sense. The whole Hula Valley is under plant cover since the late 1950s of which 48 × 103 dunams are presently tree covered (groves). The Golan Heights area is tree covered (grove and vineyard) by about 74.5 × 103 dunams. Consequently, total tree covered area of the Upper Jordan Watershed Upstream during 2017 is about 123 × 103 dunams. A small quantity of water (14–17 × 106 m3 ) is also conveyed from headwater sources (Hula Valley Western Canal) to irrigate crops on the Dalton Plateau (Western part of the Upper Galilee). Water consumption for irrigation in this part of Israel is fully monitored and absolutely restricted to legislated permission.

## **4.2 Vegetation cover changes in the Hula Valley**

Water supply for irrigation on the Golan Heights (part of the upper Jordan watershed) is precipitation-dependent. Thirty-two reservoirs (total capacity 34 mcm; 106 m3 ) were constructed on the Golan Heights to store natural runoff water. Therefore, maximum water reduction from the Kinneret budget is 34 mcm/y. The maximum reduction of water removal from the Kinneret budget attributed to the increase in vegetation cover is worth only to 20 cm of the lake water level. Maximum storage in the Golan reservoirs occurs when regional precipitation is surplus while all other resources are plentiful and Kinneret WL is increasing anyhow.

Givati [1] documented the decline of 77 mcm/y of Dan and Banias river (major sources of River Jordan) discharges and an annual decrease of precipitations on the Golan Heights of 246 mm during 1970–2010 (Mean 6.2 mm/y).

A reasonable option for invisible water loss in the Hula Valley is the underground preferential pathways gravitating subterranean water migration. Gophen [3, 4] and Gophen et al. [2] suggested 38 mcm/y water loss during drought seasons in the Hula Valley. The Kinneret water balance management was optimized between the dependents of natural parameters (precipitations and river discharge) and human demands (agriculture and domestic). The lake water level resulted in the fluctuations caused by those fluctuating parameters. The national supply (direct pumping from the lake and northern consumption) continued until a severe long-term (5 years) drought led to insufficiency; then a desalinization solution was implemented. Throughout this long-term process, Galilee and the Golan were populated, followed by agricultural flourishing, and the lake was not devastated.

Calculated drought level using the SPI (standard precipitation index) scale during 1930–2016 [1] indicated 13 and 17 years of severe drought during 1930–1970 and 1970–2016, respectively; it also indicates climate change.

The search for well-known cases of water level (WL) decline in lakes is common among limnologists and hydrologists. Deterioration of water quality quite often by water level decline is accompanied by other factors. However, shrinkage measure of the lake is closely related to the Bathymetric features of the lake. In shallow lakes with a flat bottom surface (such as the Aral Sea and Lake Chad), a minor decline of WL exposes a vast bottom area and extreme shrinkage while in deep lakes (steep bottom surface) the opposite occurs: exceptional WL decline exposes a smaller area of the bottom surface. A WL amplitude fluctuation of 20 m (197–217 mbsl) in

**143**

**Author details**

Moshe Gophen

MIGAL, Scientific Research Institute, Kiryat Shmone, Israel

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: gophen@migal.org.il

provided the original work is properly cited.

*The Synergistic Impact of Climate Change and Anthropogenic Management on the Lake…*

Lake Kinneret during 9000 years did not threaten its existence as much as a decline of 19.5 m in Lake Sivan (Armenia). Water utilization for agriculture sometimes (Aral Sea and Lake Chad) led to a huge shrinkage in water bodies, while in other cases (Kinneret, Sivan), a much smaller shrinkage occurs. The top priority of Lake Kinneret exploitation is water supply for domestic use. Removal of water from the Kinneret budget for agricultural development north of the lake by the national authority has led to exceptional shrinkage of Lake Kinneret, which is not realistic. Insufficient replenishment of the Kinneret storage capacity by reduction in water

The impact of climate change in the Upper Jordan Watershed was precipitation and consequently river discharges and available water capacities since the mid-1980s decline [14–16]. Regional air temperature increase was accompanied by the elevation of Lake Kinneret water temperatures. The ET regime during 2005-2018 in the Hula Valley was approximately stable (± 10%). Air temperature increase did not caused significant fluctuations of the ET values due to the high density of vegetation cover which reduced soil surface warming. The changes of the ecological Lake Kinneret trait were mostly due to nutrient dynamics of limitation shift from

*DOI: http://dx.doi.org/10.5772/intechopen.86512*

inputs is due mostly to climate change.

**5. Conclusive remarks**

Phosphorus to Nitrogen.

*The Synergistic Impact of Climate Change and Anthropogenic Management on the Lake… DOI: http://dx.doi.org/10.5772/intechopen.86512*

Lake Kinneret during 9000 years did not threaten its existence as much as a decline of 19.5 m in Lake Sivan (Armenia). Water utilization for agriculture sometimes (Aral Sea and Lake Chad) led to a huge shrinkage in water bodies, while in other cases (Kinneret, Sivan), a much smaller shrinkage occurs. The top priority of Lake Kinneret exploitation is water supply for domestic use. Removal of water from the Kinneret budget for agricultural development north of the lake by the national authority has led to exceptional shrinkage of Lake Kinneret, which is not realistic. Insufficient replenishment of the Kinneret storage capacity by reduction in water inputs is due mostly to climate change.
